Systems, methods, and devices for health monitoring of an energy storage device

ABSTRACT

A monitoring device for a battery pack, which includes a plurality of battery cells, has at least one ultrasound source and at least one ultrasound sensor. The ultrasound source can be configured to generate and direct ultrasound at one or more battery cells of the battery pack. The ultrasound sensor can be configured to detect ultrasound reflected from or transmitted through one or more cells of the battery pack. A battery management unit receives one or more signals from the ultrasound sensor responsive to the detected ultrasound. The battery management unit can be configured to determine a state of the battery pack based at least in part on the detected ultrasound.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/912,113, filed Feb. 15, 2016, which is a national stage entry ofInternational Application No. PCT/US2014/051013, filed Aug. 14, 2014,which claims the benefit of U.S. Provisional Application No. 61/866,300,filed Aug. 15, 2013, all of which are hereby incorporated by referenceherein in their entireties.

FIELD

The present disclosure relates generally to health monitoring of anenergy storage device, and, more particularly, to ultrasonic assessmentof lithium-ion battery cells to monitor a state of health.

SUMMARY

Systems, methods, and devices for monitoring a state of health of anenergy storage device, such as a lithium-ion battery cell, are disclosedherein. In general, an ultrasonic acoustic source and sensor can bedisposed proximal to a surface of a battery cell, which may be part of alarger battery pack. The ultrasonic source and sensor can be used tonondestructively assess the internal condition of vital interfacesinside the battery cell. These interfaces can include the interfacebetween the anode active material, the cathode material, and therespective current collector (e.g., a metallic current collector).Alternatively or additionally, the ultrasonic source and sensor can beused to monitor battery swelling, electrode expansion, and/or electroderuffling among other things. The resulting information can used todetermine a state of health of the battery cell and/or the battery pack.The information about the extent of degradation can be used forpredicting the reliability and/or the remaining useful life of thebattery cell and/or battery pack.

In one or more embodiments of the disclosed subject matter, a healthmonitoring device comprises an ultrasound source and an ultrasoundsensor. The ultrasound source is configured to generate and directultrasound at an energy storage device. The ultrasound sensor isconfigured to detect ultrasound reflected from or transmitted throughthe energy storage device and to generate a signal responsive to thedetected ultrasound from the energy storage device.

In one or more embodiments of the disclosed subject matter, a method ofmonitoring an energy storage device comprises applying ultrasound to anenergy storage device and detecting ultrasound reflected from ortransmitted through the energy storage device. The method furthercomprises generating a signal indicative of the detected ultrasound.

In one or more embodiments of the disclosed subject matter, a batterysystem with state of health monitoring comprises a battery pack, one ormore ultrasonic health monitoring devices, and a battery managementsystem. The battery pack comprises a plurality of individual lithium-ionbattery cells. Each ultrasonic health monitoring device is arranged toassess one of the lithium-ion battery cells and includes an ultrasoundsource that directs ultrasound at the respective lithium-ion batterycell. Each ultrasonic health monitoring device further includes anultrasound sensor that detects ultrasound reflected from or transmittedthrough the respective lithium-ion battery cell and generates a signalresponsive thereto. The battery management system is configured toreceive the signal from each ultrasound sensor and to determine a stateof health of the battery pack based at least in part on said signal.

Objects and advantages of embodiments of the disclosed subject matterwill become apparent from the following description when considered inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will hereinafter be described with reference to theaccompanying drawings, which have not necessarily been drawn to scale.Where applicable, some features may not be illustrated to assist in theillustration and description of underlying features. Throughout thefigures, like reference numerals denote like elements.

FIG. 1A is a simplified conceptual illustration of discharging of alithium-ion battery.

FIG. 1B is a simplified conceptual illustration of charging of alithium-ion battery.

FIG. 2A is a diagram illustrating an internal arrangement ofinterdigitated electrode layers within an example of a battery cell.

FIG. 2B is a simplified diagram of a battery cell in an as-manufacturedstate of health.

FIG. 2C is a simplified diagram of a battery cell deviating from amanufactured state of health due to ruffling of the electrode layers.

FIG. 2D is a simplified diagram of a battery cell deviating from amanufactured state of health due to swelling and ruffling of theelectrode layers.

FIG. 2E is a simplified diagram of a battery cell deviating from amanufactured state of health due to swelling.

FIG. 3A is a simplified diagram of a battery health monitoring device ina transmitted ultrasound configuration, according to one or moreembodiments of the disclosed subject matter.

FIG. 3B shows a battery health monitoring device in a hand-heldtransmitted ultrasound configuration, according to one or moreembodiments of the disclosed subject matter.

FIG. 4 is a simplified diagram of a battery health monitoring device ina reflected ultrasound configuration, according to one or moreembodiments of the disclosed subject matter.

FIG. 5 is a simplified diagram of a battery health monitoring device ina transmitted and reflected ultrasound configuration, according to oneor more embodiments of the disclosed subject matter.

FIG. 6 is a simplified diagram of a battery health monitoring device inan offset reflected pulse configuration, according to one or moreembodiments of the disclosed subject matter.

FIG. 7 is a simplified diagram of a battery health monitoring device inan offset transmitted ultrasound configuration, according to one or moreembodiments of the disclosed subject matter.

FIG. 8 is a simplified diagram of a battery health monitoring devicewith a single source and multiple sensors in a transmitted ultrasoundconfiguration, according to one or more embodiments of the disclosedsubject matter.

FIG. 9 is a simplified diagram of a battery health monitoring devicewith multiple sources and sensors in a transmitted ultrasoundconfiguration, according to one or more embodiments of the disclosedsubject matter.

FIG. 10 is a simplified diagram of a battery health monitoring devicewith multiple transducers in a staggered arrangement, according to oneor more embodiments of the disclosed subject matter.

FIG. 11 is a graph illustrating an example of a profile for charging anddischarging of a lithium ion battery.

FIG. 12A is a graph illustrating changes in battery capacity versuscycles of charge and discharge for a tested lithium ion battery cell.

FIG. 12B is a graph illustrating examples of changes in battery capacityversus cycles of charge and discharge for various lithium ion batterycells.

FIG. 13 is a graph of amplitude response detected by a battery healthmonitoring device for an ultrasonic pulse transmitted through a lithiumion battery cell in an as-manufactured state of health.

FIG. 14 is a graph of amplitude response detected by a battery healthmonitoring device for an ultrasonic pulse transmitted through a lithiumion battery cell in a compromised state of health.

FIG. 15 is a simplified diagram of a battery system having multiplebattery cells with a battery health monitoring device for each batterycell, according to one or more embodiments of the disclosed subjectmatter.

FIG. 16 is a simplified diagram of a battery system having multiplebattery cells with a battery health monitoring device for only some ofthe battery cells, according to one or more embodiments of the disclosedsubject matter.

FIG. 17 is a simplified diagram of an automotive battery systememploying battery health monitoring devices, according to one or moreembodiments of the disclosed subject matter.

FIG. 18 is a simplified diagram illustrating mounting of an ultrasoundcomponent to a battery cell, according to one or more embodiments of thedisclosed subject matter.

FIG. 19 is a simplified diagram illustrating flexible coupling of anultrasound component to a battery cell, according to one or moreembodiments of the disclosed subject matter.

FIG. 20 is a simplified diagram of a generalized setup for interrogatinga battery cell for determining a state of health thereof, according toone or more embodiments of the disclosed subject matter.

FIG. 21 is a simplified diagram of a setup for sequentiallyinterrogating multiple battery cells for determining a state of healththereof, according to one or more embodiments of the disclosed subjectmatter.

DETAILED DESCRIPTION

In one or more embodiments of the disclosed subject matter, an energystorage device, such as a battery cell (e.g., a lithium-ion batterycell), can be non-destructively assessed using ultrasound in order todetermine a state of health or other information regarding the interiorstructure of the energy storage device. In some embodiments, theultrasonic assessment may occur while the energy storage device is inuse (e.g., during charging or discharging of the battery cell) so as toprovide real-time information regarding the state of health of theenergy storage device in the field. Control or use of the energy storagedevice may be altered in response to the real-time information, forexample, to take corrective action to address imminent failure of theenergy storage device. Alternatively or additionally, the informationcan be used to predict reliability or determine the remaining usefullife of a system incorporating the energy storage device, for example, abattery pack with multiple battery cells. In other embodiments, theultrasonic assessment may occur when the energy storage device is notyet in service, for example, as part of a field return evaluation ormanufacturing quality control. In any of the embodiments, healthmonitoring can be accomplished by monitoring confidence values computedby applying statistical pattern recognition techniques to the transientbehavior of battery cells, transient responses, and correlation of theresponses with models and validated with experimental data.

To perform the ultrasonic assessment of the energy storage device,ultrasonic pulses generated by an ultrasound source (e.g., an ultrasoundpulser or transducer) can be focused at specific depths within theenergy storage device to be assessed. As the acoustic wave approaches aninterface within the energy storage device, the acoustic wave may bepartially or totally reflected. Such interfaces may be associated withchanges in the internal volume of the energy storage device caused bydelamination, voiding, or other phenomena. The intensity of thereflected wave and/or transmitted wave is a function of the acousticimpedance of the interface. The reflected and/or transmitted waves canthus provide a measure of changes in the internal structure of theenergy storage device that may be indicative of imminent failure orincreasing degradation.

Lithium Ion Batteries

In one or more embodiments of the disclosed subject matter, the energystorage device is a battery cell, for example, a lithium-ion batterycell. Lithium-ion battery cells are free of many of the deficienciesfrom which other rechargeable battery cells suffer, such as highself-discharge rates and memory effects due to partial charge anddischarge. In addition, because of their high energy density, long cyclelife, and battery cell voltage, lithium-ion cells have been adopted foruse in portable electronics as well as automotive applications, forexample, as an energy storage device for all-electric or hybridvehicles.

FIGS. 1A-1B are schematic diagrams of discharging and chargingconfigurations, respectively, to illustrate various structuresassociated with a lithium-ion battery cell 100. In general, alithium-ion battery cell 100 can include one or more cathode layers 104,one or more anode layers 102, respective current collectors on which thelayers 102, 104 are disposed, a separator 106, and electrolytes 108filling the interior volume of the battery cell 100. The electrolytes108 can include a mixture of organic carbonate solvents (e.g., ethylenecarbonate and dimethyl carbonate) and polymer salts (e.g., LiPF₆), whichprovide conductivity for the transport of lithium ions 110 between theelectrodes 102, 104. Electrical contact between the internal electrodes102, 104 is made via anode terminal 112 and cathode terminal 114,respectively, which are disposed external to the interior volume of thebattery cell.

During the charging process (FIG. 1B), a current 118 is supplied to thecathode terminal 114 via a charging power source 126. Electron flow 120is from the cathode terminal 114 to the charging power source 126. Thecathode 104 has a high standard redox potential. As a result the current118 and electron flow 120, the transition metal of the cathode 104 isoxidized and lithium ions 110 b diffuse through the separator 106 to theanode 102, where they are intercalated into layers of, for example,carbon graphite to form Li_(x)C₆.

During the discharging process (FIG. 1A), a load 116 is connectedbetween the cathode terminal 114 and the anode terminal 112. As aresult, the electron flow 120 is from the anode terminal 112 to thecathode terminal 114 while the current 118 is in the opposite direction.As a result, the transition metal of the cathode 104 is reduced. Inaddition, lithium ions 110 a are deintercalated from the anode 102 andmove though the electrolyte 108 and the separator 106 back to thecathode 104.

It is to be appreciated that FIGS. 1A-1B are simplified illustrations ofthe inner workings of a lithium-ion battery cell and that practicalembodiments of a lithium-ion battery cell will include more complexarrangements than those illustrated. For example, the cathode andelectrode layers can be arranged in an interdigitated fashion, withalternating layers of anode and cathode electrodes in a thicknessdirection of the battery cell. Such a battery cell 200 is illustratedschematically in FIG. 2A. Thus, the anode layers 202 are arrangedbetween adjacent cathode layers 204, and vice versa. Each anode layer202 and each cathode layer 204 may be connected (in parallel or inseries) to the anode terminal 212 and the cathode terminal 214,respectively, which provides electrical connection to a load or chargingdevice located external to the battery cell. A separator layer (notshown) is provided between each adjacent cathode 204 and anode 202. Themulti-layered electrode separator structure 220 sits in an electrolytesolution within an interior volume of the battery cell 200 and operatesin a similar manner as described above with respect to FIGS. 1A-1B.

For simplicity of illustration and explanation, the electrodes andseparator (including their arrangement and number) in the followingdrawings have been simplified as a number of parallel lines and referredto generally as 220. However, other arrangements and configurations forthe structure of the battery cell beyond those specifically illustratedand discussed are also possible according to one or more contemplatedembodiments. For example, the battery cell may have a so-called buttonconfiguration. In the button configuration, the battery cell may besubstantially cylindrical with a top surface of the cylinder serving asone electrode terminal and a bottom surface of the cylinder serving asthe other electrode terminal. The electrode layers within the buttoncell can be arranged perpendicular to an axis of the button cell, asannular layers extending along the axis of the button cell, or in anyother arrangement. In another contemplated embodiment, the battery cellneed not have clearly delineated electrode layers within the interiorvolume thereof. For example, the interior volume of the battery cell maybe filled with a slurry and electrode terminals can extend into theinterior volume to provide electrical contact thereto. In anotherexample, the interior volume of the battery cell may comprise lumps ofmaterial rather than planar electrodes. Such configurations may sufferfrom similar degradation as the planar electrode configurationsdiscussed above. One of ordinary skill in the art will appreciate thatother battery cell configurations are also possible and will benefitfrom assessment using the disclosed ultrasonic health monitoring devicesand techniques.

Despite advances in materials, packaging technologies and statemonitoring solutions, many challenges regarding reliable use oflithium-ion battery cells remain. Over the lifecycle of a lithium-ionbattery cell, various thermal, mechanical, and electrochemical processescontribute to the degradation of the cell's performance. Lithium-ionbatteries generally begin to degrade almost immediately after completionof manufacturing and continue to degrade during storage and use.Degradation due to self-discharge, which occurs during storage as wellas during charge/discharge cycling, may depend on the ambienttemperature, storage time, and the state of charge of the cell (e.g.,fully charged, partially charged, fully discharged, etc.). Additionaldegradation during charge/discharge cycles can be accelerated based onhigh-temperature exposure, frequent charge/discharge cycles, deepdischarge (i.e., approaching fully discharged before recharging), andovercharge (i.e., charging beyond a designated capacity of the batterycell).

Vital interfaces where degradation may occur inside a lithium-ionbattery cell include the interface between the metallic currentcollector and the active material for both the anode and cathode.Internal resistance can increase with complex chemical reactions betweenthe active materials, electrodes, and the electrolyte. Battery materialsmay also be susceptible to expansion during charging. As a result, theanode or cathode layers within the battery cell may delaminate fromtheir respective current collector, thereby causing a shift in chargeand discharge properties of the battery.

FIG. 2B depicts a battery cell 200 a in an as-manufactured state.Battery cell 200 a thus has a set initial thickness and an orderedarrangement of electrode layers 220 within the internal volume of thebattery cell. However, with continued charge and discharge cycles,swelling, delamination, or other degradation can occur.

FIG. 2C shows a battery cell 200 b that has degraded after multiplecharging/discharging cycles. In particular, the electrode layers 220have deformed resulting in electrode ruffling. Volumetric expansion ofthe electrode particles can cause localized stress concentrations thatruffle the electrode. This can cause a loss of connectivity between theelectrode active material particles and the electrically conductiveparticles included in the electrode matrix. Separation or delaminationof the electrode material and the current collector can occur. As aresult, the useful capacity of the battery cell decreases due to itsreduced charge-transfer capabilities.

FIG. 2D shows another battery cell 200 c that has degraded aftermultiple charging/discharging cycles. For example, localized heating andabusive operating conditions can result in the release of gas speciesthat can cause volumetric expansion and/or venting of the cell torelieve internal pressure. If the battery cell is overcharged, thecathode can become unstable and the electrolyte can decompose.Alternatively or additionally, if the battery cell is overdischarged,the current collector (e.g., made of copper) can dissolve and causeinternal short circuiting. As a result, local hotspots within the cellmay be created that cause a variety of chemical reactions that releasegas as a by-product. The gas release can cause ruffling of the electrodelayers 220, similar to that illustrated in FIG. 2C, and may furthercause a swelling of a housing of the battery cell 200 c, therebyresulting a change in thickness of the battery cell 200 c and/orlocalized deformation of one or more surfaces of the housing of thebattery cell 200 c. In some cases, swelling of the housing of thebattery cell 200 d may be present without significant ruffling of theelectrode layer 220, as illustrated schematically in FIG. 2E.

In worst case scenarios, rapidly increasing temperatures and excessivegas generation can cause the cell to explode and catch fire. However,many cells exhibit less severe levels of gas generation over theirlifetime. This gas generation contributes to internal structural changesto the cell that can degrade the battery over its life cycle. Forexample, gas pockets in cycled cells can lead to a degradation due todisplacement of the electrodes, thereby making it more difficult totransport ions through the electrolyte. Additionally, porosity in theelectrode can increase thereby lowering connectivity between adjacentelectrode material particles.

A significant consequence of this degradation is a drop in the capacityof the battery cell as it is charged and discharged. As used herein,capacity of a battery cell refers to the maximum current that a batterycell can supply over a given time period and is commonly expressed inampere-hours (Ah). For example, if a battery cell is rated for 1000 mAh,then it should be capable of supplying 1000 mA over a one-hour periodbefore it needs recharging. While capacity rating provides a basis forwhat type of battery can best meet the needs of a particular system, itonly provides a measure of the battery's initial capabilities. Anydecrease in capacity due to degradation of the battery cell duringstorage and/or use will compromise the battery's ability to delivereffectively store and deliver energy.

Given the chemical, mechanical and thermo-dynamic processes that occurwithin the battery cell and contribute to the degradation, the batterycell can be monitored to provide real-time information. For example,metrics of interest for real-time monitoring include amount ofdegradation in battery capacity as well as, but not limited to, amountof remaining charge in a battery and remaining useful battery life.Knowledge of the internal state of the battery cell can help determinecharging times, appropriate discharge strategies, balancing betweendifferent cells in a battery pack, and/or thermal management within abattery pack.

The current capacity of a battery cell over the as-manufactured orinitial capability can be used to define one metric for a battery cell'sstate of health. The state of health metric reflects the degradation ofthe battery and/or the battery pack and can be based on a decrease inthe available capacity that a battery can deliver or an increase in theinternal resistance thereof. The state of health metric can bedetermined using data obtained by measuring the voltage and currentduring the charge and discharge stages and estimating, for example, thedecay in capacity and state of health based on current, voltage, andtemperature measurements. In general, a 20% decrease in deliverablecapacity can represent a threshold beyond which the battery performancebegins to deteriorate rapidly. While a decrease in the deliverablecapacity or an increase in internal resistance may reflect degradationin a lithium-ion battery system, this only relates to reducedperformance and does not address safety. Gas generation and changes tothe structure of the cell also capture performance-related informationas well as information related to unsafe conditions that could beexacerbated as the battery cell is further stressed. Thus, investigationof the internal cell structure can help provide a more complete state ofhealth evaluation that includes decreases in both performance andsafety.

Battery Health Monitoring Device

Embodiments of the disclosed subject matter can use ultrasonicassessment of the internal structure of an energy storage device, forexample, a battery cell, in order to provide information regarding astate of health of the assessed battery cell. Such information can beused alone or in conjunction with other state of health metrics toprovide a more complete picture of the state of health of a battery cellor a battery pack including multiple battery cells.

Ultrasonic assessment detects changes in acoustic impedance, such as aninterface between two materials, through measurement of reflected and/ortransmitted acoustic signals. Modes of assessment can include apulse-echo mode, a through-transmission mode, or both. In the pulse-echomode, a sensor is arranged to detect ultrasound reflected from theinterior of the battery cell. In the through-transmission mode, a sensoris arranged to detect ultrasound transmitted through the interior of thebattery cell (e.g., by being located opposite the ultrasonic source oron a side of the battery cell opposite the ultrasonic source). In eithermode, the source and sensor are configured to generate and detect,respectively, sound having a frequency in the ultrasound range, forexample, greater than 1 MHz.

These assessment modes can be used to assess, among other things,swelling, electrode expansion, electrode delamination, voiding, and/orelectrode ruffling within an assessed battery cell. These degradationmechanisms may be related to degradation resulting from, for example,typical charge/discharge cycling, intermittent operation at an elevatedtemperature that may be within or above specified operating limits, ormechanical and thermomechanical stresses acting on the cell during itsoperation. Based on the detected ultrasound, a metric can be providedfor the degradation within the battery cell. For example, the amplitudeof the reflected pulse and/or transmitted pulse can be used as a metricto assign a degradation level to the electrodes within the battery.Alternatively or additionally, a controller can make a determinationabout the state of health of the battery cell based on the detectedultrasound alone or along with other information regarding operatingcharacteristics of the battery cell.

The ultrasonic source (e.g., a pulser or transducer) can emit pulses ofultrasonic energy at a specific frequency. Selection of the appropriateultrasonic source and the corresponding assessment frequency can bebased on the battery cell to be investigated, including among otherthings, the thickness of the battery cell, the geometry of the batterycell, and the temperature of assessment. Generally, a lower frequencytransducer can be used to penetration into thick, more attenuating,and/or highly scattering battery cell materials, and a higher frequencytransducer can be used for thinner, lower attenuating, and/or lowerscattering battery cell materials. The ultrasonic source can be providedadjacent to an external surface of the battery cell and arranged todirect the ultrasonic energy into the interior of the battery cell. Forexample, an emission direction of the ultrasonic energy may beperpendicular to the plane of one or more electrode layers within theinterior of the battery cell.

The ultrasonic sensor (e.g., a transducer) can detect ultrasonic energyin a broad range of ultrasound frequencies or limited to the specificfrequency emitted by the ultrasonic source. As with the ultrasonicsource, the ultrasonic sensor can be provided adjacent to an externalsurface of the battery cell and arranged to detect ultrasonic energycoming from the interior of the battery cell, e.g., reflected ortransmitted ultrasound. In some embodiments, the ultrasonic source andthe ultrasonic sensor can be parts of a single transducer, for example,for use in a pulse-echo mode configuration. In other embodiments, thesource and sensor can be separate components disposed at differentportions on the battery cell.

The ultrasonic source and/or the ultrasonic sensor can be disposed onthe battery cell through a respective couplant. For example, thecouplant may be disposed between and in contact with an external surfaceof the battery cell and a corresponding active surface of the ultrasonicsource and/or the ultrasonic sensor. Thus, ultrasound traveling to orfrom the battery cell would pass through the couplant. The couplantprovides a pathway to/from the battery cell for the ultrasound in orderto avoid attenuation due to exposure of the ultrasound to air or otherhigh attenuation mediums, which may otherwise compromise assessment ofthe battery cell. The couplant may be a separate component, for example,an encapsulated gel or gel pad, that is placed between the battery celland the source or sensor, or attached to the source, sensor, or batterycell surface. Alternatively, the couplant may be integrated with thesource or the sensor, e.g., as the material of an emission or detectionface thereof.

Appropriate couplants can be selected based on acoustic velocity,impedance, and attenuation, as well as other factors, for example, asdiscussed in “Approximate Material Properties in Isotropic Materials,”published in IEEE Transactions on Sonics and Ultrasonics, May 1985,SU-32(3): pp. 381-94, which is hereby incorporated by reference herein.In some embodiments, the couplant is a hydrocarbon grease. In otherembodiments, the couplant is a pad of encapsulated gel. For example, thegel pad includes one or more polymers having an attenuation with respectto the applied ultrasonic frequencies similar to or approaching that ofwater. The gel can be a dry couplant elastomer comprising a blend ofisomers of branched homopolymers with an attenuation of 5 dB relative towater, for example, as described in “Ultrasonic Properties of a New LowAttenuation Dry Couplant Elastomer,” by Ginzel et al., April 1994, whichis also incorporated by reference herein in its entirety. Other examplesof couplants include but are not limited to the Water Gel UltrasoundSolid Gel Pad by BlueMTech (BlueMTech, Korea) and the AquaFlex®Ultrasound Gel Pad (Parker Laboratories, USA). Other couplants can alsobe used according to one or more contemplated embodiments.

The detected ultrasound from the battery cell may be evaluated as eitheran A-scan or C-scan. In general, A-scans can provide a determination ofthe state of health of the battery cell, and C-scan can be used to imagean interior of the battery cell, for example, to visualize and locateregions of degradation. As used herein, A-scan refers to an amplitudemodulation scan, i.e., the actual waveform of the acoustic signalobtained by the sensor. After application of an ultrasonic pulse to thebattery cell, the resulting detected signal can be graphed where thehorizontal axis is time and the vertical axis is amplitude.

In contrast, C-scan refers to scanning the transducer in one or twodimensions, e.g., raster-scanning the source/sensor over the entiresurface area of the battery cell to produce a digitized image. Afterapplication of an ultrasonic pulse at each scanned position, theresulting detected signal at a particular time (corresponding to aparticular depth in the battery cell, for example, as determined byplacement of the data gate) is graphed to provide a map of the interfaceat that depth. The data gate targets an interface of interest within thethickness of the sample through the assessment of a portion of thecorresponding A-scan waveform. For example, the interface of interestcan be defined by positioning a rectangular frame over the portion ofthe A-scan that corresponding with the interface of interest usingappropriate image processing software. The larger the time valueassociated with the data gate on the time axis of the A-scan, thegreater the depth of interface of interest within the battery cell. Bymoving the gate position in time on the A-scan, different depths withinthe sample can be imaged. If air, gas, or another medium is present at aparticular interface, all of the ultrasonic signal from that particularregion may be reflected back, which results in detectable areas on aC-scan. The presence of air or gas pockets due to inner delaminatedregions or voids will also cause the shape of the A-scan waveforms,which are taken at different points over the interface of interest, tobe different in the data-gate region. In cases of extreme delaminationor separation between active material and corresponding currentcollector, a phase inversion of the A-scan signal occurs at thedata-gate region.

In one or more embodiments, a battery health monitoring device usestransmitted ultrasound to assess the internal volume of a battery cell,as described above, to make a determination regarding the state ofhealth of the battery. For example, the battery health monitoring device300 can be configured in a through-transmission mode for interrogatingbattery cell 200, as shown in FIG. 3A and FIG. 3B. The battery cell 200may be connected to a load or charger 302 via terminals 212, 214 suchthat the battery cell 200 may be assessed while the battery cell 200 isin use, for example, during discharging or charging.

An ultrasound source 304 is disposed on a first side of the battery cell200 with a couplant 306 between the battery cell 200 and the source 304.For example, an ultrasonic pulse 308 from the source 304 may be directedsubstantially perpendicular to the plane of one or all electrode layers220 within the interior of the battery cell. Alternatively oradditionally, at least an emission face of the source 304 is arrangedsubstantially parallel to an external surface of the battery cell 200and/or the plane of one or all electrode layers 220 within the interiorof the battery cell 200.

The ultrasound sensor 310 can be disposed on a second side of thebattery cell 200 opposite to the first side and arranged to receive theultrasonic pulse 308 transmitted through the interior volume of thebattery cell 200. Although not shown, the sensor 310 may also bedisposed with a couplant between the battery cell 200 and the sensor310. The sensor 310 can be arranged directly opposite to the source 304so as to receive ultrasound 308 traveling in a straight line through thethickness of the battery cell 200, i.e., from a first side of thebattery cell 200 facing the source 304 to a second side of the batterycell 200 facing the sensor 310.

A controller 312 (i.e., control unit) can be provided to controloperation of the ultrasound source 304 and the ultrasound sensor 310 andto determine a state of health of the battery cell 200 based on signalsfrom the ultrasound sensor 310. For example, the controller 312 maycommand the ultrasound source 304 to apply an ultrasonic pulse to thebattery cell 200. The ultrasound sensor 310 can generate a signal basedon detected ultrasound and convey the signal to the controller 312,which may use the signal to compose an A-scan. The resulting A-scan canbe evaluated based on timing and/or amplitude of the detected pulse, forexample, to make a determination regarding state of health of thebattery cell 200. Such evaluation can include, but is not limited to, acomparison of the resulting A-scan with a previously obtained A-scan,which may be an A-scan of the battery cell 200 that was taken when thebattery cell was in an as-manufacture or as-delivered non-cycled state.The controller 312 can also be configured to control the battery cell200, for example, to alter charging, discharging, or other operations ofthe battery cell based on its determined state of health.

The source 304 and the sensor 310 can be disposed to assess one portionof the interior of the battery cell 200, for example, where structureswithin the interior of the battery cell 200 may be especiallysusceptible to degradation. Alternatively or additionally, the source304 (and couplant 306) and the sensor 310 can move along a length (i.e.,from left to right in FIG. 3A) and/or a width (i.e., into or out of thepage in FIG. 3A) of the battery cell 200 to assess different portions ofthe battery cell 200. For example, the source 304 and the sensor 310 canmove in order to obtain a C-scan of the battery cell 200 in order toimage a particular defect or degradation. Controller 312 may control thesource 304 and/or the sensor 310, for example, through an appropriatedisplacement mechanism, to provide the desired movement.

In one or more additional embodiments, a battery health monitoringdevice uses reflected ultrasound to assess the internal volume of abattery cell, as described above, to make a determination regarding thestate of health of the battery. For example, the battery healthmonitoring device 400 can be configured in a pulse-echo mode forinterrogating battery cell 200, as shown in FIG. 4. As with thepreviously described embodiment, the battery cell 200 may be connectedto a load or charger 302 via terminals 212, 214 such that the batterycell 200 may be assessed while the battery cell 200 is in use, forexample, during discharging or charging.

A transducer 402 is disposed on a first side of the battery cell 200with a couplant 306 between the battery cell 200 and the transducer 402.The transducer 402 includes both an ultrasound source portion 404 and anultrasound sensing portion 410. Although shown as separate portions, itis contemplated that the source portion 404 and the sensing portion 410can be the same structure, for example, an active portion of thetransducer 402 that serves an emitter when the ultrasound is emitted andthen serves as a sensor after the ultrasound pulse is emitted.

For example, the ultrasound 308 (e.g., an ultrasonic pulse) from thesource portion 404 may be directed substantially perpendicular to theplane of one or all electrode layers 220 within the interior of thebattery cell. Alternatively or additionally, at least anemission/detection face of the transducer 402 is arranged substantiallyparallel to an external surface of the battery cell 200 and/or the planeof one or all electrode layers 220 within the interior of the batterycell 200. The sensing portion 310 receives ultrasound 408 reflected fromstructures (e.g., electrode layers 220) within the interior volume ofthe battery cell 200.

A controller 312 can be provided to control operation of the transducer402 and to determine a state of health of the battery cell 200 based onsignals from the transducer 402. For example, the controller 312 maycommand the transducer 402 to apply an ultrasound 308 to the batterycell 200. The transducer 402 can generate a signal based on detectedultrasound and convey the signal to the controller 312, which may usethe signal to compose an A-scan. The resulting A-scan can be evaluatedbased on timing and/or amplitude of the detected energy, for example, tomake a determination regarding state of health of the battery cell 200.Such evaluation can include, but is not limited to, a comparison of theresulting A-scan with a previously obtained A-scan, which may be anA-scan of the battery cell 200 that was taken when the battery cell wasin an as-manufacture or as-delivered non-cycled state. The controller312 can also be configured to control the battery cell 200, for example,to alter charging, discharging, or other operations of the battery cellbased on its determined state of health.

The transducer 402 can be disposed to assess one portion of the interiorof the battery cell 200, for example, where structures within theinterior of the battery cell 200 may be especially susceptible todegradation. Alternatively or additionally, the transducer 402 (andcouplant 306) can move along a length (i.e., from left to right in FIG.4) and/or a width (i.e., into or out of the page in FIG. 4) of thebattery cell 200 to assess different portions of the battery cell 200.For example, the transducer 402 can move in order to obtain a C-scan ofthe battery cell 200 in order to image a particular defect ordegradation. Controller 312 may control the transducer 402, for example,through an appropriate displacement mechanism, to provide the desiredmovement. Alternatively or additionally, the transducer 402 may be fixedwhile the battery cell 200 is moved with respect to the transducer 402to assess different portions of the battery cell 200. For example, thetransducer can include a roller or wheel-shaped contact portion, such asbut not limited to the Olympus Roller Ultrasonic Transducer (e.g., partnumber RT-0105-16SY by Olympus Corporation).

In one or more additional embodiments, a battery health monitoringdevice can use transmitted and reflected ultrasound, eithersimultaneously or sequentially, to assess the internal volume of thebattery cell to make a determination regarding the state of health ofthe battery cell. For example, the battery health monitoring device 500,as shown in FIG. 5, can combine the through-transmission assessmentfeatures of the embodiment of FIGS. 3A-3B and the pulse-echo assessmentfeatures of the embodiment of FIG. 4. As with the previously describedembodiments, the battery cell 200 may be connected to a load or charger302 via terminals 212, 214 such that the battery cell 200 may beassessed while the battery cell 200 is in use, for example, duringdischarging or charging. In addition, as with the previously describedembodiments, the device 500 can be disposed to assess a single portionof the battery cell 200, or the device 500 and/or the battery cell 200can be moveable to assess different portions of the battery cell 200,for example, to obtain a C-scan.

The controller 312 controls operation of the transducer 402 and sensor310 and determines a state of health of the battery cell 200 based onsignals from the transducer 402 and sensor 310. For example, thecontroller 312 may command the transducer 402 to apply an ultrasonicpulse 308 to the battery cell 200. Transducer 402 generates a signalbased on detected, reflected ultrasound 408 and conveys a first signalto the controller 312, while sensor 310 generates a signal based ondetected, transmitted ultrasound 308 and conveys a second signal to thecontroller 312. The controller 312 may use the first and second signalsto determine a state of health of the battery cell, for example, byevaluating timing and/or amplitude in the detected signals and/or bycomparison to previously obtained A-scans. For example, the controller312 can use reflected ultrasound signals to localize degradation planeswithin the battery cell 200 while the transmitted ultrasound signals areused to measure the degree of degradation within the battery cell 200.The controller 312 can also be configured to control the battery cell200, for example, to alter charging, discharging, or other operations ofthe battery cell based on its determined state of health.

In one or more additional embodiments, a battery health monitoringdevice 600 uses reflected ultrasound to assess the internal volume of abattery cell 200, as shown in FIG. 6. Similar to the embodiment of FIG.4, battery health monitoring device 600 is configured in a pulse-echomode for interrogating battery cell 200. However, the ultrasound source604 and the ultrasound sensor 610 are separate from each other andspaced on a first side of the battery cell 200. The ultrasound source604 is disposed with an angled couplant 606 between the battery cell 200and the source 604. The couplant 606 supports the source 604 in anangled configuration with respect to the surface of the battery cell 200and/or the electrode layers 220 therein. Thus, the ultrasonic pulse 308from the source 604 may be directed at an angle (i.e., not perpendicularor parallel) with respect to one or all electrode layers 220 within theinterior of the battery cell. Alternatively or additionally, at least anemission face of the source 604 is arranged at angle with respect to anexternal surface of the battery cell 200 and/or the plane of one or allelectrode layers 220 within the interior of the battery cell 200.

The ultrasound sensor 310 can be arranged to receive ultrasound 608reflected from structures (e.g., electrode layers 220) within theinterior volume of the battery cell 200. The ultrasound sensor 310 canbe arranged with an active face thereof parallel to an external surfaceof the battery cell 200 and/or the plane of one or all electrode layers220 within the interior of the battery cell 200, as shown in FIG. 6.Alternatively, the ultrasound sensor 310 may have an angledconfiguration similar to that of ultrasound source 604, but shifted tobe aligned with a direction of the reflected ultrasound 608.

As with the previously described embodiments, controller 312 can beprovided to control operation of the source 604 and the sensor 610 andto determine a state of health of the battery cell 200 based on signalsfrom the sensor 610. The battery cell 200 may be connected to a load orcharger 302 via terminals 212, 214 such that the battery cell 200 may beassessed while the battery cell 200 is in use, for example, duringdischarging or charging.

The source 604 and the sensor 610 can be disposed to assess one portionof the interior of the battery cell 200, for example, where structureswithin the interior of the battery cell 200 may be especiallysusceptible to degradation. Alternatively or additionally, the source604 (and couplant 606) and the sensor 610 can move along a length (i.e.,from left to right in FIG. 6) and/or a width (i.e., into or out of thepage in FIG. 6) of the battery cell 200 to assess different portions ofthe battery cell 200. For example, the source 604 and the sensor 610 canmove in order to obtain a C-scan of the battery cell 200 in order toimage a particular defect or degradation. Alternatively or additionally,the angle of the source 604 (or the angle of the sensor 610, whenangled) can be varied to assess different portions of battery cell 200.Controller 312 may control the source 604 and/or the sensor 610, forexample, through an appropriate angling and displacement mechanism, toprovide these desired movements.

In one or more additional embodiments, a battery health monitoringdevice 700 uses transmitted ultrasound to assess the internal volume ofa battery cell 200, as shown in FIG. 7. Similar to the embodiment ofFIG. 3A, battery health monitoring device 700 is configured in athrough-transmission mode for interrogating battery cell 200. However,the ultrasound source 604 and the ultrasound sensor 710 are spaced fromeach other in a length direction of the battery cell. The ultrasoundsource 604 is disposed with an angled couplant 606 between the batterycell 200 and the source 604. The couplant 606 supports the source 604 inan angled configuration with respect to the surface of the battery cell200 and/or the electrode layers 220 therein. Thus, the ultrasonic pulse308 from the source 604 may be directed at an angle (i.e., notperpendicular or parallel) with respect to one or all electrode layers220 within the interior of the battery cell. Alternatively oradditionally, at least an emission face of the source 604 is arranged atangle with respect to an external surface of the battery cell 200 and/orthe plane of one or all electrode layers 220 within the interior of thebattery cell 200.

The ultrasound sensor 710 can be arranged to receive ultrasound 308transmitted through the interior volume of the battery cell 200. Theultrasound sensor 710 can be arranged with an active face thereofparallel to an external surface of the battery cell 200 and/or the planeof one or all electrode layers 220 within the interior of the batterycell 200, as shown in FIG. 7. Alternatively, the ultrasound sensor 710may have an angled configuration parallel to that of ultrasound source604 so as to be aligned with a direction of the transmitted ultrasound608.

As with the previously described embodiments, controller 312 can beprovided to control operation of the source 604 and the sensor 710 andto determine a state of health of the battery cell 200 based on signalsfrom the sensor 710. The battery cell 200 may be connected to a load orcharger 302 via terminals 212, 214 such that the battery cell 200 may beassessed while the battery cell 200 is in use, for example, duringdischarging or charging.

The source 604 and the sensor 710 can be disposed to assess one portionof the interior of the battery cell 200, for example, where structureswithin the interior of the battery cell 200 may be especiallysusceptible to degradation. Alternatively or additionally, the source604 (and couplant 606) and the sensor 710 can move along a length (i.e.,from left to right in FIG. 7) and/or a width (i.e., into or out of thepage in FIG. 7) of the battery cell 200 to assess different portions ofthe battery cell 200. For example, the source 604 and the sensor 710 canmove in order to obtain a C-scan of the battery cell 200 in order toimage a particular defect or degradation. Alternatively or additionally,the angle of the source 604 (or the angle of the sensor 710, whenangled) can be varied to assess different portions of battery cell 200.Controller 312 may control the source 604 and/or the sensor 710, forexample, through an appropriate angling and displacement mechanism, toprovide these desired movements.

In one or more additional embodiments, a battery health monitoringdevice 800 uses transmitted ultrasound to assess the internal volume ofa battery cell 200, as shown in FIG. 8. Similar to the embodiment ofFIG. 3A, battery health monitoring device 800 is configured in athrough-transmission mode for interrogating battery cell 200. However,an array 810 of ultrasound sensors 310 is provided on the opposite sideof the battery cell 200 from the ultrasound source 304. For example, theultrasonic pulse 308 from the source 304 may be directed substantiallyperpendicular to the plane of one or all electrode layers 220 within theinterior of the battery cell. Alternatively or additionally, at least anemission face of the source 304 is arranged substantially parallel to anexternal surface of the battery cell 200 and/or the plane of one or allelectrode layers 220 within the interior of the battery cell 200.

An ultrasound sensor 310 can be arranged to directly opposite theultrasound source 304 so as to receive the ultrasound pulse 308transmitted through the interior volume of the battery cell 200. Theremaining ultrasound sensors 310 of the array 810 can be arranged toreceive any spreading 808 of the ultrasound 308, for example, due toexpansion of the ultrasound wave in the interior of the battery cell 200and/or scattering or deflection by internal structures (e.g., electrodelayers 220) of the battery cell. Each ultrasound sensor 310 can bearranged with an active face thereof parallel to an external surface ofthe battery cell 200 and/or the plane of one or all electrode layers 220within the interior of the battery cell 200, as shown in FIG. 8.

As with the previously described embodiments, controller 312 can beprovided to control operation of the source 304 and the sensors 310 andto determine a state of health of the battery cell 200 based on signalsfrom the sensors 310. The battery cell 200 may be connected to a load orcharger 302 via terminals 212, 214 such that the battery cell 200 may beassessed while the battery cell 200 is in use, for example, duringdischarging or charging.

The source 304 can be disposed to assess one portion of the interior ofthe battery cell 200, for example, where structures within the interiorof the battery cell 200 may be especially susceptible to degradation.Alternatively or additionally, the source 304 (and couplant 306) and,optionally one or more of sensors 310 of the array, can move along alength (i.e., from left to right in FIG. 8) and/or a width (i.e., intoor out of the page in FIG. 8) of the battery cell 200 to assessdifferent portions of the battery cell 200. For example, the source 304can move with respect to the sensor array 810, with different sensors310 of the array serving as the sensor directly opposite the source 304as the source 304 moves, in order to obtain a C-scan of the battery cell200 and to image a particular defect or degradation. Controller 312 maycontrol the source 304 and/or the sensor array 810, for example, throughan appropriate displacement mechanism, to provide these desiredmovements.

In an alternative embodiment, multiple sources 304 can be provided as anarray 904 similar to the array 810 of sensors 310, as illustrated in thebattery health monitoring device 900 of FIG. 9. In such a configuration,each source 304 of the source array 904 may be arranged opposite to andcorrespond to a particular sensor 310 of the sensor array 810. Toprevent cross-talk between adjacent sensors 310, each source 304 may beactivated separately such that the corresponding through pulse 308 isdetected by the corresponding sensor 310 before the next source 304 inthe array is activated. Alternatively, sources 304 with sufficientspacing between each other may be activated at the same time, where thespacing minimizes the amount of cross-talk that may be detected by thecorresponding sensors 310. For example, every other source 304 in array810 may be actuated at the same time. In yet another alternative,sources 304 may be simultaneously activated and the sensors 310 of thearray 810 simultaneously sampled and the resulting signals used incombination by the controller 312 to determine a state of health.

In still another alternative embodiment, multiple sources can beprovided as a source array similar to that illustrated FIG. 9, but withmultiple sensors corresponding to each source of the source array. Thus,the number of sensors in the sensor array may be more than the number ofsources in the source array. For example, each source can have a primarysensor disposed directly opposite thereto and secondary sensors with theprimary sensor therebetween, but the secondary sensors do not have asource disposed directly opposite thereto. Activation of each source maybe sequential or simultaneous, for example, as described above withrespect to FIG. 9.

In one or more additional embodiments, a battery health monitoringdevice 1000 uses reflected ultrasound to assess the internal volume of abattery cell 200, as shown in FIG. 10. Similar to the embodiment of FIG.4, battery health monitoring device 1000 is configured in a pulse-echomode for interrogating battery cell 200. However, a first array 1002 aof ultrasound transducers 402 is provided on a first side of the batterycell 200, and optionally, a second array 1002 b of transducers 402 canbe provided on a second side opposite to the first side. Each transducer402 may emit a pulse 308 into the interior of the battery cell 200 andcan detect the resulting reflection from internal structures (e.g.,electrode layers 220) within the battery cell 200.

To prevent cross-talk between adjacent transducers 402, each transducer402 may be activated separately such that the corresponding reflectedpulse 408 is detected by the same transducer 402 before the nexttransducer 402 in the array 1002 a or 1002 b is activated.Alternatively, transducers 402 with sufficient spacing between eachother may be activated at the same time, where the spacing minimizes theamount of cross-talk that may be detected by the transducers 402. Forexample, every other transducer in each array 1002 a, 1002 b may beactuated at the same time. In yet another alternative, transducers 402on one side of the battery cell 200 may be simultaneously activated. Forexample, the transducers 402 in array 1002 a may be simultaneouslyactivated and signals from transducers 402 in array 1002 asimultaneously sampled.

In another example, transducers 402 in array 1002 b can serve as throughultrasound sensors for the pulses emitted by transducers 402 in array1002 a. For example, each transducer 402 in array 1002 b can receive anyspreading 808 of the ultrasound 308, for example, due to expansion ofthe ultrasound wave in the interior of the battery cell 200 and/orscattering or deflection by internal structures (e.g., electrode layers220) of the battery cell. Alternatively, each transducer 402 in array1002 b may be arranged directly opposite to a corresponding transducer402 in array 1002 a in order to receive transmitted pulse 308 directly.Thus, such a configuration may allow simultaneous pulse-echo andthrough-transmission detection with assessment from opposite sides ofthe battery cell.

As with the previously described embodiments, controller 312 can beprovided to control operation of the source 304 and the sensors 310 andto determine a state of health of the battery cell 200 based on signalsfrom the sensors 310. The battery cell 200 may be connected to a load orcharger 302 via terminals 212, 214 such that the battery cell 200 may beassessed while the battery cell 200 is in use, for example, duringdischarging or charging.

Other configurations and arrangements of components of a battery healthmonitoring device beyond those specifically discussed above are alsopossible according to one or more contemplated embodiments. For example,the embodiment of FIG. 10 can be modified to include an array 1002 a oftransducers 402 only a single side of the battery cell 200. Othervariations and combinations will be apparent to one of ordinary skill inthe art, and embodiments of the disclosed subject matter are not limitedto the specific embodiments illustrated in the drawings and describedherein.

Although shown and described separately, it is contemplated thatelements of the health monitoring device may be provided as one or moreintegral units. For example, the control unit can be integrated with theultrasound source and/or the ultrasound sensor. In another example, thesource, the sensor, and the control unit may comprise a singletransducer with appropriate integrated circuitry for controllingoperation of the source and sensor and processing the resulting signals.In yet another example, the control unit is separate from an integratedunit of the ultrasound source and the ultrasound sensor, and the controlunit receives the signals from the integrated unit, for example, ahard-wired connection, over the Internet, or via a wireless connection.In still another example, the control unit comprises a separate modulewithin a common housing of the source and the sensor. In any of thecontemplated embodiments and examples, the health monitoring device canbe provided as a handheld unit, for example, with individual manuallypositioned parts, as shown in FIG. 3B, or as an integrated unit that auser manually brings into contact with a particular battery cell.

EXAMPLES

Tests were performed on commercial lithium-ion batteries having anominal voltage of 3.7 V. The electrodes were in a stackedconfiguration, and the separator was folded over in an accordion-likefashion so as to separate the stacked anode and cathode electrodes fromeach other. The anode and cathode materials were thus contained inalternating folds of the separator. Additionally, the anode and cathodematerials were connected in series. Cell failure was defined as a dropin capacity of less than 80% (e.g., less than 75% or less than 72.5%) ofthe manufacturer-specified nominal capacity.

Continuous battery charge/discharge cycling tests were performed using acommercial battery tester (e.g., a Cadex C8000) having four independentchannels. The continuous cycling test was performed at a rate of 0.5 C.In addition to the cells that were charged and discharged at 0.5 C, afew uncycled, as-received cells were used as controls for periodicphysical evaluation and comparisons. In accordance with the protocolsdescribed in UL 1642 and IEEE 1725, the batteries were cycled at roomtemperature to the specification of the manufacturer. Baseline capacitymeasurements were taken to ensure that full rated capacity was usedduring charging and discharging cycles. FIG. 11 shows an example of aconstant current/constant voltage protocol that was used to charge anddischarge the batteries. While the discharge mode occurred as a constantcurrent load, actual operating conditions resulted in a variable currentbeing applied to the battery.

In one example of a battery under test, a sharp drop in capacity wasseen after the 76^(th) cycle of the continuous charge/discharge cyclingprofile, as illustrated in FIG. 12A. There were no additional stressesplaced on the cell, such as overcharging, overdischarging, or anincrease in ambient temperature. Despite having this sudden drop incapacity during the 76^(th) cycle, the cell did not reach the predefinedfailure threshold (e.g., 75% capacity) until after 133 cycles. A visualexamination of the cell showed the cell had an increased externalthickness as compared to the control battery cells. The change inthickness that was observed in the cycled cell was attributed toelectrode ruffling and gas evolution within the cell. It is to be notedthat the change in capacity illustrated in FIG. 12A is only an example,and other battery cells may have faster capacity loss rate (e.g.,Battery 3, Battery 4) or slower capacity loss rate (e.g., Battery 1,Battery 2) until a predefined failure threshold (e.g., 72.5% capacity)is reached, as illustrated in FIG. 12B.

Ultrasonic assessment was performed on cycled and uncycled cells. Theultrasonic transducers were able to detect changes in acousticimpedance, such as at an interface between two materials, where aportion of the ultrasonic signal would be reflected back while theremainder would be transmitted through the interface and detected viathrough transmission. A portable digital ultrasonic sensor instrumentwas used to obtain A-scans of the acoustic signal. A handheld assessmentsetup is shown in FIG. 3B. The cell was first disconnected from theCadex C8000 battery tester and then connected to the ultrasonicdetection setup. A 5 MHz, ¼-in. diameter ultrasonic pulser transducerwas placed on top of the cell, and a 5 MHz, ¼-in. diameter ultrasonicreceiver was placed on the bottom, as shown in FIG. 3B. Ahydrocarbon-based grease was used as a couplant at the interfaces of thepulser and receiver with the outer casing of the cell. Thethrough-transmission parameters are shown in Table 1 below.

TABLE 1 Examples of Parameters for Ultrasonic Assessment of Lithium IonBattery Cell Parameter Value Ultrasound Source (e.g., Pulser) 5 MHz,¼-in diameter Ultrasound Sensor (e.g., Receiver) 5 MHz, ¼-in diameterUltrasound Frequency 5 MHz Energy 400 V Damping 400 Ω Receiver Filter1.5 MHz to 8.5 MHz Gain 50 dB

After the cell was set up for through transmission, an A-scanrepresentation was obtained on the display of the portable ultrasonicsensor. An A-scan from a non-cycled, as-manufactured control cell isshown in FIG. 13. As is apparent from FIG. 13, a strong through-pulsewas detected by the receiver transducer, which pulse is consistent withthe fact that the cell was uncycled and thus had not yet experienced anydegradation. FIG. 14 shows an A-scan of the cycled cell that exhibitedthe drop in capacity after the 76^(th) cycle. As is apparent from FIG.14, the cycled cell transmitted only a very weak, delayed pulse. Theweakening of the input ultrasonic pulse amplitude sensed by the receivertransducer suggests that the interfaces within the cell degraded due toat least one of electrode expansion, gas evolution, and residual stressdeveloping along the interfaces as the cell is cycled. Thus, informationfrom ultrasonic assessment of a cell can be used to evaluate theinternal condition of structures of the cell and thereby provide ameasure of the state of health of the cell.

Systems with Battery Health Monitoring

A battery-management system (BMS) can be incorporated into a host systemthat uses single cells or banks of cells arranged in series, parallel,or combinations thereof. A BMS enables safer and reliable operation byperforming, among other things, state monitoring, charge control, andcell balancing (in multi-cell pack systems). Since certain batteryoperations (e.g., over-discharge) can reduce cell capacity, the BMS canmonitor and control the battery cells based on safety circuitryincorporated within the battery pack to avoid such damaging operations.For example, whenever any abnormal conditions are detected, such asovervoltage or overheating, the BMS can notify the user and/or executethe predetermined corrective procedures.

The BMS can use one or more sensors to monitor battery conditions andcan determine a state of health of individual batteries or the entirebattery back responsive to signals from the sensors. Cells connectedtogether in a battery pack may not be easily accessible once assembled.Thus, physical examination of individual cells for structural changesmay require disassembly of the battery pack, which, in general, may notbe safely performed by an end user. However, the disclosed ultrasonichealth monitoring device provides information on the internal structuralchanges of a monitored battery cell. Thus, a BMS that incorporatesinformation from the ultrasonic health monitoring device can improveoverall safety and/or reliability of the battery pack. Early faultdetection can help the BMS inform the user when to implement repair andmaintenance strategies to prolong the life of the battery pack and/oravoid further degradation that could result in imminent or eventualbattery failure.

As noted above, the battery cell being monitored can be a part of alarger battery pack that includes multiple battery cells connected inseries, parallel, or any combination thereof. The ultrasonic transducerscan be used to nondestructively and noninvasively monitor and assess theinternal state of vital battery interfaces, e.g., the interface betweenthe current collector and the corresponding anode and cathode materials.The ultrasonic data can be used to determine the instantaneous safetyand health of the battery pack, for maintaining the battery system,and/or for evaluating the state of health over the course of the batterypack's lifetime.

In one or more embodiments, a battery system employs a battery healthmonitoring device, for example, one or more of the battery healthmonitoring devices described above, to monitor individual battery cellswithin a battery pack. For example, the battery system 1500 can have abattery pack 1504 with a plurality of battery cells 200, each with acorresponding ultrasonic health monitoring device 1502, as shown in FIG.15. The battery pack 1504 can be connected to a load or charging device(not shown). The ultrasonic health monitoring devices 1502 can thusassess and monitor the individual battery cells 200 while the batterypack 1504 is in use (e.g., charging or discharging).

Signals from the respective ultrasonic health monitoring devices 1502can be conveyed to controller 312, where a determination of the state ofhealth of each battery cell 200 can be made, for example, as describedabove. The battery system 1500 can also include a battery control module1506, which regulates operation of the individual battery cells 200within the battery pack 1504. Controller 312 may communicate state ofhealth determinations to the battery control module 1506 for use incontrolling operation of the individual battery cells 200. For example,battery control module 1506 may control charging and/or dischargingprofiles of each cell 200 and/or shut-down particular cells 200 inresponse to safety or reliability concerns. Together with controller312, battery control module 1506 may form a battery management system(BMS) 1508, which may receive additional information regarding thebattery cells 200 in determining appropriate operation or a state ofhealth of the battery pack 1504. For example, in response to signalsfrom the ultrasonic health monitoring devices 1502 indicative of thestates of health for the various battery cells, the BMS 1508 can controlcharging/discharging within the battery pack 1504 to avoid defective ordegraded cells 200, can determine an overall state of health of thebattery pack 1504 or remaining useful lifetime for the battery pack1504, and/or can provide an external alert regarding a degraded ordangerous condition of one of the battery cells 200 or the battery pack1504.

Additionally, the BMS 1508 can receive signals from other sensors (notshown) that monitor one or more performance characteristics of thebattery cells 200 and/or the battery pack 1504 in determining the stateof health of the cells and/or the battery pack. For example, theperformance sensors can be configured to measure battery cell internalresistance, battery cell discharge profile, battery cell charging time,battery cell current or voltage, battery cell temperature, battery cellstrain, battery cell dimensions, or gas venting from the battery celland to generate a measurement signal responsively thereto. Using theinformation from the performance sensors in combination with theinformation from the ultrasonic health monitoring devices 1502 canprovide a more complete picture of the state of health of eachindividual battery cell 200 and the battery pack 1504 overall.Alternatively or additionally, health monitoring can be accomplished bymonitoring confidence values computed by applying statistical patternrecognition techniques to the transient behavior of battery cells,transient responses, and correlation of the responses with models andvalidated with experimental data.

As with the ultrasonic health monitoring devices, performance sensorsmay be provided for each device. Alternatively, one or only some of thebattery cells 200 are provided with performance sensors. For example,the performance sensors may be provided to one or more battery cells 200within the pack 1504 that are more susceptible to degradation.Alternatively or additionally, one or more of the performance sensorsmay be shared among multiple battery cells 200. For example, a singletemperature sensor may be provided for the entire battery pack 1504 or asubset of battery cells 200 within the battery pack 1504 and can measurea temperature that is associated with each of the battery cells 200.

In yet another alternative, one or only some of the battery cells 200can be provided with ultrasonic health monitoring devices, for example,as with battery system 1600 in FIG. 16. In contrast to the embodiment ofFIG. 15, only the subset 1602 of the plurality of battery cells 200 areprovided with an ultrasonic health monitoring device 1502. The number ofbattery cells 200 within subset 1602 that receive an ultrasonic healthmonitoring device may be limited, for example, to no more than one-thirdof the total battery cells 200 within pack 1504, and may be even furtherlimited to less than 10%.

The controller 312 can use information from the ultrasonic healthmonitoring devices 1502 associated with the subset 1602 to infer orpredict the state of health of the remaining cells 200 within thebattery pack 200. For example, the ultrasonic health monitoring devicesmay be provided to one or more battery cells 200 within the pack 1504that are more susceptible to degradation. In such an example, presumablythe degradation of battery cells 200 outside the subset 1602 would beless than the degradation of battery cells 200 within the subset 1602,such that information from the ultrasonic health monitoring devices 1502represents a worst-case scenario for the battery pack 1504.

In one or more embodiments, a battery system with in-situ ultrasonichealth monitoring is provided in an automotive application, for example,as an energy source for a hybrid-electric or all electric vehicle. Forexample, an automobile system 1700 can have a battery pack 1504 with aplurality of battery cells 200, as shown in FIG. 17. The battery pack1504 can be connected to an electric motor 1716, which drives wheels ofthe vehicle. An engine controller 1706 monitors and regulatesperformance of the electric motor 1716, for example, in response todrive conditions or user input.

Ultrasonic health monitoring devices 1502 are provided to a subset 1602of the battery cells 200 for interrogating and monitoring a state ofhealth of the cells 200 and the battery pack 1504, as described above.In addition, performance sensors 1704 are provided to some of thebattery cells 200 for interrogating and monitoring performancecharacteristics of the battery cells 200. A performance sensor signalprocessor 1702 receives signals from the performance sensors and conveysinformation regarding the performance characteristics to the batterycontrol module 1506 responsively thereto. For example, the performancesensors can be configured to measure at least one of battery celldischarge profile, battery cell charging time, battery cell current orvoltage, and battery cell temperature and to generate a measurementsignal responsively thereto.

One or more performance sensors may be associated with a same batterycell 200 as one of the ultrasonic health monitoring devices 1502, forexample, performance sensor 1704 b monitoring battery cell 200 in subset1602. Alternatively or additionally, one or more performance sensors maybe associated only with a battery cell 200 that is not monitored by oneof the ultrasonic health monitoring devices 1502, for example,performance sensor 1704 a.

Selection of the subset 1602 of cells 200 that are to receive anultrasonic health monitoring device and/or a performance sensor may bebased on, for example, susceptibility to degradation or exposure todegrading conditions. The most vulnerable cells in the battery pack maybe a result of the particular arrangement of the cell 200 in the batterypack 1504, for example, cells 200 that are arranged closer to an engine1716 or that may see higher temperatures than other cells 200 in thepack 1504. The subset 1602 of sampled cells 200 can be used to predict astate of health of entire battery pack 1504, or can be used to provide afault indication if one of the monitored cells in the subset 1602catastrophically fails or is in danger of imminent failure. For example,sampling may be such that less than 5% of cells 200 are monitored. In anexample, the number of battery cells 200 in battery pack 1504 isthree-hundred and only between five and ten, inclusive, of the totalnumber of battery cells 200 in the pack 1504 are monitored.

The output signals from the ultrasonic health monitoring devices 1502can be integrated into the an automotive battery management system(aBMS) 1708, which can include, among other things, ultrasonic healthmonitoring controller 312, performance sensor signal processor 1702, andbattery control module 1506. In the case of an automobile, by selectiveplacement of such ultrasonic health monitoring devices 1502 on thebattery cells 200 within the battery pack 1504, the onboard aBMS 1708can provide indicators that show the state of the health, usage,performance, and longevity of the battery pack 1504.

Using the techniques described herein, the aBMS 1708 can providereal-time, in-situ monitoring of representative batteries (e.g., subset1602) within the battery pack 1504. When an abnormal condition isdetected, such as an electrode delamination beyond a set threshold orbattery cell swelling due to overheating, the aBMS 1708 can notifyonboard safety systems (e.g., via engine controller 1706 or otheronboard controllers), execute a set of corrective procedures (e.g., viabattery control module 1506), and/or notify a user, operator,manufacturer or other external entity (e.g., via user interface 1710).For example, the user interface 1710 may comprise an on-board dashboardindicator. Alternatively or additionally, the user interface 1710 is acommunication device that allows transmission of data to an externalcomputer or system, for example, a wireless connection to a user'ssmartphone or an Internet transmission to the automobile manufacturer.In addition to providing alarms due to adverse events, incorporation ofthis technique allows real-time recording of degradation within therepresentative battery cell 1502 of the battery pack 1504.

In one or more embodiments, the ultrasonic health monitoring device canbe arranged on a surface of the battery cell 200 or battery pack 1504.For example, a battery configuration 1800 can have the ultrasonic healthmonitoring device mounted on an exterior surface 1802 of battery cell200, as shown in FIG. 18. The exterior surface 1802 can include amounting portion 1804 that retains the ultrasonic source 304 and thecouplant 306 to the exterior surface 1802. A similar mounting portionmay be provided for the sensor 310 (not shown), when necessary for athrough-transmission configuration.

As noted above, the couplant 306 can comprise an encapsulated gel pad orinsert. Such gel pads may enjoy a relatively long lifetime and may bereusable depending on the application. The couplant 306 can bepre-attached to or integral with the ultrasonic source 304 so that thecombination of the source 304 and couplant 306 are inserted into themounting portion 1804 at the same time. Alternatively, the couplant 306may be a separate piece and inserted into the mounting portion 1804before the source 304.

For example, the mounting portion 1804 may comprise a screw mechanism,locking mechanism, epoxy, glue, or any other retaining mechanism thatcan rigidly couple the ultrasonic health monitoring device to thesurface. As the exterior surface 1802 moves, for example, due toswelling or other internal deformations, the mounting portion 1804allows the ultrasonic health monitoring device to follow the movement ofthe exterior surface 1802.

Alternatively, the ultrasonic health monitoring device can be flexiblymounted so as to follow movement of the exterior surface 1802, as shownin the configuration 1900 of FIG. 19. For example, the ultrasonic sourceor transducer 402 can be provided with an annular lip 1902. A spring1906 can provide an axially biasing force between lip 1902 and mountingsupport 1904 (e.g., a portion of the automotive body or other supportstructure independent of the particular battery cell 200) that urges thetransducer 402 and couplant 306 into contact with the exterior surface1802 of the battery cell 200. Movement of the exterior surface 1802 isaccommodated by corresponding compression of spring 1906. Additionally,the movement of the transducer 402, which may be monitored bydisplacement sensors, for example, can provide an additional indicatorof state of health of the battery cell 200, i.e., by providing a measureof the swelling of surface 1802. A similar configuration may be providedfor the sensor 310 (not shown), when necessary for athrough-transmission configuration.

Battery Health Testing Systems

In one or more embodiments, a testing system employs a battery healthmonitoring device, for example, one or more of the battery healthmonitoring devices described above, to test individual battery cells, aspart of a field return evaluation or quality control of a manufacturingprocess. For example, a battery testing system 2000 can have a testingplatform 2002 with a first support 2004 for a first portion of anultrasound health monitoring device and a second support 2006 for asecond portion of the ultrasound health monitoring device, as shown inFIG. 20. For example, the first support 2004 may support the ultrasoundsource 304 and couplant 306 above the battery cell 200 and the secondsupport 2006 may support the ultrasound sensor 310 below the batterycell 200, or vice versa.

In some configurations, only one of the first and second supports 2004,2006 can be provided, for example, when only a pulse-echo mode isemployed for testing the battery cells 200. Alternatively oradditionally, an additional support (not shown) may be provided to holdbattery cell 200 for assessment by the ultrasonic health monitoringdevice. One or more of the supports (when provided) may be configured tomove in at least one dimension, for example, to bring the couplant 306and ultrasound source 304 into contact with a first surface of thebattery cell 200 and to bring the ultrasound sensor 310 into contactwith a second surface of the battery cell 200. The couplant 306 can be,for example, a gel pad attached to an end of the ultrasonic source 304,which is brought into contact with each individual battery cell 200conveyed to the testing platform 2002.

A controller 2012 can control the testing platform 2002 to move thesupport portions 2004, 2006 and/or battery cell 200 to performultrasonic assessment thereof. For example, the controller 2012 cancontrol a conveying device (not shown) to move a battery cell 200 from abatch of cells to the testing platform 2002 for assessment. Thecontroller 2012 can then control the testing platform 2002 to bring thecouplant 306 and/or the sensor 310 into contact with the battery cell200 and to subject the battery cell 200 to an ultrasonic pulse from thesource 304. Alternatively or additionally, the source 304 and/or thesensor 310 may comprise a roller transducer, such as the OlympusUltrasonic Roller Transducer referenced above. In such a configuration,the battery cell 200 may be linearly displaced between the rollingcontact surfaces of the roller transducer to perform an assessment.Alternatively or additionally, the roller transducers can be displacedwith respect to the battery cell 200 in order to perform an assessment.

The controller 2012 can receive a signal from sensor 310 indicative ofthe detected ultrasound and can provide an indication of the state ofhealth, as described above. The controller 2012 can direct the batterycell 200 from the testing platform 2002 and/or provide an indication(e.g., a visual or auditory signal) based on a result of the assessment.Alternatively or additionally, the controller 2012 can move theultrasonic health monitoring device and/or the battery cell 200 to allowassessment of more than one location within the interior of the batterycell 200, for example, by raster scanning across the surface of thebattery cell 200.

In some embodiments, the battery cell 200 can be manually placed withinthe testing platform 2002 for evaluation. The controller can thencontrol the testing platform 2002 to bring the couplant 306 into contactwith the battery cell 200. In other embodiments, the testing platform2002 can be actuated manually, for example, by a user moving one or moreof the supports 2004, 2006 to contact the ultrasonic health monitoringdevice with the battery cell. Alternatively or additionally, the testingsystem 2000 can be configured as a handheld testing unit where a usercan bring the testing platform 2002 into contact with the battery cell200, for example, by inserting battery cell 200 into a receptacle of ahandheld testing platform 2002.

In still other embodiments, the testing platform 2002 may have one ormore of the supports 2004, 2006 that can passively move in response to athickness of the battery cell 200 arranged between the supports 2004,2006. For example, at least one of the supports 2004, 2006 can be springmounted with a spacing between a surface of couplant 306 and a facingsurface of the couplant (not shown) associated with sensor 310 beingless than a thickness of the battery cell 200. Insertion of the batterycell 200 between the couplants biases the source 304 and sensor 306against the respective surfaces of the battery cell 200.

In one or more embodiments, a testing system 2100 can optionally includea selection device that selects individual battery cells from aplurality of battery cells for respective assessment by the ultrasoundsource and sensor. For example, the selection device can include aconveying device 2106 that moves the battery cell 200 to a testingplatform 2104, as shown in FIG. 21. For example, the conveying device2106 can comprise a conveyor belt on which multiple battery cells 200 tobe tested are disposed. As described above, the testing platform 2104can ultrasonically test each individual battery cell 200 by bringing theultrasonic health monitoring device 2102 into contact with the batterycell 200. The controller 2112 receives signals from the ultrasonichealth monitoring device 2102 indicative of an internal condition of theassessed battery cell 200 and can control conveying device 2106 todirect the assessed battery cell 200 from the testing platform 2104based thereon.

For example, battery cells 200 that do not meet predetermined criteriacan be directed to a defect or reject bin while those that do meet thepredetermined criteria can be directed to an acceptable bin for furtherprocessing. A redirection unit 2108 can have an arm 2110 that pushes arejected battery cell 200 as it moves from the testing platform 2104 inorder to move the rejected battery cell 200 via a different conveyorpath 2114 to the reject bin. Acceptable battery cells 200 can continuealong conveyor path 2116 to the acceptable bin. Other mechanisms forconveying the battery cells 200 to/from the testing platform 2104 andfor redirecting the battery cells based on measured status are alsopossible according to one or more contemplated embodiments. For example,the conveying device can comprise a reel.

When the battery cell is a returned or reprocessed battery cell (i.e.,one that has already undergone multiple charge/discharge cycles and/orhas been stored for a significant period of time after manufacture), thecontroller (e.g., controller 2012 in FIG. 19 or controller 2112 in FIG.20) may determine based on the detected ultrasound signal if the stateof health of the battery cell 200 is sufficient for reuse (e.g., thatthe capacity of the battery cell has not degraded below 80%). Such stateof health assessment can evaluate for degradation due to gas generation,active material delamination, electrode buckling, lithium ion diffusion,separator shrinkage, lithium plating, and tab shifting, for example.Those battery cells that are determined to be insufficient for reuse maybe directed, for example, to a waste bin for proper disposal.

When the battery cell is a new battery cell (i.e., one that has notundergone multiple charge/discharge cycles and/or has been stored for ashort period of time after manufacture), the controller (e.g.,controller 2012 in FIG. 19 or controller 2112 in FIG. 20) may determinebased on the detected ultrasound signal if the battery cell meetscertain quality control criteria. Such quality control assessment caninclude determining the presence and location of metal particleinclusions, excessive current collector overhang, poor tab welds,agglomeration of active material, uneven thickness of active material,for example. Those battery cells that are determined to have qualitycontrol flaws may be directed, for example, to a defect bin forreprocessing.

Embodiments of the disclosed subject matter have been described abovewith respect to lithium-ion battery cells having a stacked electrodeconfiguration and a substantially rectangular exterior shape. However,this discussion is merely intended to illustrate the principles andtechniques of the disclosed systems, methods, and devices. The disclosedprinciples and techniques are also applicable to other battery cellconfigurations and other energy storage devices, and the abovedescription should not be understood as limiting the present disclosureto lithium-ion batteries. For example, the energy storage device mayhave an interior volume comprised of a slurry without a well-definedelectrode configuration. In another example, the energy storage devicemay have an exterior shape that is substantially spherical, oval,elliptical, or any other shape. In such configurations, the source andsensor may be disposed on the same surface, for example, at the samelocation (e.g., as part of the same transducer) or at differentpositions on the same surface (e.g., as separate transducers). Otherstructures and shapes are also possible according to one or morecontemplated embodiments.

In addition, although embodiments have been described where eachultrasonic health monitoring device assesses a single battery cell,embodiments of the disclosed subject matter are not limited thereto.Rather, more than one battery cell can be disposed for assessment by asingle ultrasonic health monitoring device. For example, in athrough-transmission mode configuration, more than one battery cell canbe stacked in a thickness direction thereof, with the ultrasound sourcedisposed on a surface of the upper-most battery cell and the ultrasoundsensor disposed on a surface of the lower-most battery cell. In anotherexample, in pulse-echo mode configuration, more than one battery cellcan be stacked in a thickness direction thereof, with a transducerdisposed on an upper-most battery cell such that reflected ultrasoundfrom battery cells in the stack can be received by the transducer. Instill another example, in pulse-echo mode configuration, more than onebattery cell can be stacked in a thickness direction thereof, with afirst transducer disposed on a upper-most battery cell and a secondtransducer disposed on a lower-most battery cell so as to be able toassess the battery cell stack from both sides thereof.

Furthermore, although specific applications of the ultrasonic healthmonitoring device have been described with respect to battery managementsystems, automotive systems, battery field testing, and quality controlassessment, embodiments of the disclosed subject matter are not limitedthereto. Rather, the ultrasonic health monitoring device can employed ina wide array of applications beyond those specifically disclosed herein,such as, but not limited to, home or office back-up battery systemmonitoring, non-automotive electric vehicles (e.g., battery poweredplanes), battery warehouse inventory monitoring, etc.

In one or more first embodiments, a battery health monitoring devicecomprises an ultrasound source, a couplant, an ultrasound sensor, and acontroller. The ultrasound source is configured to generate ultrasonicpulses having a frequency greater than 1 MHz. The couplant is arrangedto convey the ultrasonic pulses from the ultrasound source to amonitored battery cell. The ultrasound sensor is configured to detectultrasound having a frequency greater than 1 MHz and is arranged todetect ultrasound reflected from or transmitted through the monitoredbattery cell. The controller is configured to determine a state ofhealth of the monitored battery cell based on a signal from theultrasound sensor indicative of the detected ultrasound.

In the first embodiments or any other embodiment, the ultrasound sourceand the ultrasound sensor are part of a single transducer disposed on asame side of the monitored battery cell. The ultrasound sensor can bearranged to detect ultrasonic pulses reflected from an interior of themonitored battery cell.

In the first embodiments or any other embodiment, the ultrasound sourceis disposed on a first side of the monitored battery cell, and theultrasound sensor is disposed on a second side of the monitored batterycell opposite from said first side. The ultrasound sensor can bearranged to detect ultrasonic pulses transmitted through an interior ofthe monitored battery cell.

In the first embodiments or any other embodiment, the battery healthmonitoring device further comprises a second ultrasound sensorconfigured to detect ultrasound having a frequency greater than 1 MHz.The second ultrasounds sensor is arranged to detect ultrasound reflectedfrom or transmitted through the monitored battery cell. The secondultrasound source can be disposed on said first side of the monitoredbattery cell.

In the first embodiments or any other embodiment, the battery healthmonitoring device further comprises at least one additional ultrasoundsource, at least one additional couplant, and at least one additionalultrasound sensor. Each additional ultrasound source is configured togenerate ultrasonic pulses having a frequency greater than 1 MHz. Eachadditional couplant corresponds to a respective additional ultrasoundsource and is arranged to convey the ultrasonic pulses from therespective additional ultrasound source to the monitored battery cell.Each additional ultrasound sensor is configured to detect ultrasoundhaving a frequency greater than 1 MHz and is arranged to detectultrasound reflected from or transmitted through the monitored batterycell. The controller is further configured to determine the state ofhealth of the monitored battery cell based on signals from theultrasound sensor and the at least one additional ultrasound sensor.

In the first embodiments or any other embodiment, the battery healthmonitoring device further comprises a plurality of additional ultrasoundsensors. Each additional ultrasound sensor is configured to detectultrasound having a frequency greater than 1 MHz and is arranged todetect ultrasound reflected from or transmitted through the monitoredbattery cell. The ultrasound sensor and the plurality of additionalultrasound sensors are arranged in an array on a same side of themonitored battery cell.

In the first embodiments or any other embodiment, the controller isconfigured to control the ultrasound source and the ultrasound sensor toperform an A-scan and to determine the state of health based on at leastone of amplitude of the detected ultrasound and timing of the detectedultrasound.

In the first embodiments or any other embodiment, the couplant compriseshydrocarbon grease or an encapsulated gel.

In the first embodiments or any other embodiment, the battery healthmonitoring device further comprises a testing platform and a conveyingdevice. The testing platform supports one or more of the ultrasoundsource, the couplant, and the ultrasound sensor. The conveying devicemoves individual battery cells from a plurality of battery cells to thetesting platform for respective assessment by the ultrasound source andthe ultrasound sensor.

In the first embodiments or any other embodiment, the controller isfurther configured to control the conveying device to direct assessedbattery cells from the testing platform responsive to the determinedstate of health from the respective assessment.

In the first embodiments or any other embodiment, the battery healthmonitoring device further comprises a performance sensor. Theperformance sensor is configured to measure at least one of battery celldischarge profile, battery cell charging time, battery cell current orvoltage, and battery cell temperature and to generate a measurementsignal responsively thereto.

In the first embodiments or any other embodiment, the batteryperformance sensor is arranged to monitor a different battery cell fromthat monitored by the ultrasound sensor at a same time.

In the first embodiments or any other embodiment, the performance sensorand the ultrasound sensor monitor the same battery cell.

In the first embodiments or any other embodiment, the controllercomprises a battery management system for a battery pack including aplurality of individual battery cells. The controller is furtherconfigured to determine a state of health of the battery pack based onthe measurement signal from the performance sensor and the signal fromthe ultrasound sensor.

In the first embodiments or any other embodiment, the monitored batterycell comprises a lithium-ion battery cell with multiple electrodelayers. The ultrasound source is arranged so as to direct the generatedultrasonic pulses perpendicular to a plane of one or more of theelectrode layers.

In the first embodiments or any other embodiment, at least theultrasound source and the couplant are mounted on a surface of themonitored battery cell.

In the first embodiments or any other embodiment, at least theultrasound source and the couplant are coupled to a surface of themonitored battery cell so as to move with said surface.

In one or more second embodiments, a method of monitoring battery cellstate of health comprises applying one or more ultrasonic pulses througha couplant to a first side of a lithium-ion battery cell, eachultrasonic pulse having frequency greater than 1 MHz. The method furthercomprises detecting ultrasound having a frequency greater than 1 MHzthat is reflected from or transmitted through the lithium-ion batterycell using one or more ultrasound sensors coupled to the lithium-ionbattery cell, and generating a signal indicative of the detectedultrasound.

In the second embodiments or any other embodiment, the method furthercomprises determining a state of health of the lithium-ion battery cellbased at least in part on the generated signal indicative of thedetected ultrasound.

In the second embodiments or any other embodiment, the determining astate of health is based on at least one of amplitude of the detectedultrasound and timing of the detected ultrasound.

In the second embodiments or any other embodiment, the lithium-ionbattery cell is one of a plurality of cells in lithium-ion battery pack.

In the second embodiments or any other embodiment, the method comprisesmeasuring at least one of battery cell discharge profile, battery cellcharging time, battery cell current or voltage, and battery celltemperature of one of the lithium-ion battery cells. The method furthercomprises generating a measurement signal indicative of a result of saidmeasuring, and determining a state of health of the lithium-ion batterypack based on the measurement signal and the signal indicative of thedetected ultrasound.

In the second embodiments or any other embodiment, the lithium-ionbattery cell has multiple electrode layers, and the applied one or moreultrasonic pulses are directed perpendicular to a plane of at least oneof the electrode layers.

In the second embodiments or any other embodiment, at least one of theone or more ultrasound sensors is part of a transducer that generatessaid one or more ultrasonic pulses.

In the second embodiments or any other embodiment, the detectingultrasound that is reflected from or transmitted through the lithium-ionbattery cell comprises detecting one or more ultrasonic pulses reflectedfrom an interior of the monitored battery cell.

In the second embodiments or any other embodiment, the detectingultrasound that is reflected from or transmitted through the lithium-ionbattery cell comprises detecting one or more ultrasonic pulsestransmitted through an interior of the monitored battery cell.

In the second embodiments or any other embodiment, at least one of theone or more ultrasound sensors is positioned on the first side of thelithium-ion battery cell.

In the second embodiments or any other embodiment, at least one of theone or more ultrasound sensors is positioned on a side of thelithium-ion battery cell opposite from the first side.

In the second embodiments or any other embodiment, the applying one ormore ultrasonic pulses and the detecting ultrasound are such that anA-scan is performed on the lithium-ion battery.

In the second embodiments or any other embodiment, the couplantcomprises hydrocarbon grease or an encapsulated gel.

In the second embodiments or any other embodiment, the couplantcomprises a gel pad.

In the second embodiments or any other embodiment, the method comprisesattaching the couplant to an ultrasonic source configured to generatethe one or more ultrasonic pulses. The method further comprises, priorto said applying, contacting the couplant to the first side of thelithium-ion battery cell and arranging the one or more ultrasoundsensors to receive ultrasound reflected from or transmitted through thelithium-ion battery cell.

In the second embodiments or any other embodiment, the method comprisesmounting the couplant and an ultrasonic source configured to generatethe one or more ultrasonic pulses on an external surface of thelithium-ion battery cell. The mounting can be such that the couplant andthe ultrasonic source move with the external surface of the lithium-ionbattery cell.

In the second embodiments or any other embodiment, the method comprises,after the applying and detecting, repeating the applying and thedetecting on a second lithium-ion battery cell and generating a secondsignal indicative of the detected ultrasound from the lithium-ionbattery cell.

In the second embodiments or any other embodiment, the method comprises,before the repeating, at least one of: moving the second lithium-ionbattery cell to a testing platform supporting an ultrasound source thatgenerates the one or more ultrasonic pulses and the one or moreultrasound sensors, and moving the testing platform supporting theultrasound source and the one or more ultrasound sensors to the secondlithium-ion battery cell.

In the second embodiments or any other embodiment, the method comprises,after the repeating the applying and the detecting on the secondlithium-ion battery cell, directing the second battery cell from thetesting platform based on the second signal.

In the second embodiments or any other embodiment, the method comprises,at a same time as the applying one or more ultrasonic pulses anddetecting ultrasound, at least one of charging the lithium-ion batterycell, discharging the lithium-ion battery cell, and repeatedly chargingand discharging the lithium-ion battery cell.

In one or more third embodiments, a battery system with state of healthmonitoring comprises a battery pack, one or more ultrasonic healthmonitoring devices, and a battery management system. The battery packcomprises a plurality of individual lithium-ion battery cells. Eachultrasonic health monitoring device is arranged to assess one of thelithium-ion battery cells. Each ultrasonic health monitoring devicecomprises an ultrasound source that directs ultrasound at the respectivelithium-ion battery cell. Each ultrasonic health monitoring devicefurther comprises an ultrasound sensor that detects ultrasound reflectedfrom or transmitted through the respective lithium-ion battery cell andgenerates a signal responsive thereto. The battery management system isconfigured to receive the signal from each ultrasound sensor and todetermine a state of health of the battery pack based at least in parton said signal.

In the third embodiments or any other embodiment, each ultrasonic healthmonitoring device further comprises a couplant arranged between theultrasound source and a surface of the respective lithium-ion batterycell.

In the third embodiments or any other embodiment, the couplant comprisesa gel pad.

In the third embodiments or any other embodiment, each ultrasonic healthmonitoring device is mounted on a surface of the respective lithium-ionbattery cell so as to move with said surface.

In the third embodiments or any other embodiment, each ultrasound sourceis configured to generated ultrasonic pulses having a frequency greaterthan 1 MHz, and each ultrasound sensor is configured to detectultrasound having a frequency greater than 1 MHz.

In the third embodiments or any other embodiment, only some of thebattery cells in the battery pack are provided with one of theultrasonic health monitoring devices.

In the third embodiments or any other embodiment, up to 5% of thebattery cells in the battery pack are provided with one of theultrasonic health monitoring devices.

In the third embodiments or any other embodiment, each battery cell inthe battery pack is provided with one of the ultrasonic healthmonitoring devices.

In the third embodiments or any other embodiment, the battery systemfurther comprises one or more performance sensors. Each performancesensor is arranged to assess one or more of the lithium-ion batterycells. Each performance sensor is configured to measure battery cellinternal resistance, battery cell discharge profile, battery cellcharging time, battery cell current or voltage, battery celltemperature, battery cell strain, battery cell dimensions, or gasventing from the battery cell and to generate a measurement signalresponsively thereto.

In the third embodiments or any other embodiment, the battery managementsystem is configured to receive the measurement signal from eachperformance sensor and to determine the state of health of the batterypack based at least in part on said measurement signal.

In the third embodiments or any other embodiment, only a subset of thebattery cells in the battery pack are provided with one of theultrasonic health monitoring devices, and at least one performancesensors assesses one of the lithium-ion battery cells different fromsaid subset.

In the third embodiments or any other embodiment, only a subset of thebattery cells in the battery pack are provided with one of theultrasonic health monitoring devices, and at least one performancesensors assesses one of the lithium-ion battery cells within saidsubset.

In the third embodiments or any other embodiment, the ultrasound sourceand the ultrasound sensor in each ultrasonic health monitoring deviceare part of a single transducer disposed on a same side of therespective lithium-ion battery cell.

In the third embodiments or any other embodiment, at least oneultrasound sensor is arranged to detect ultrasound reflected from aninterior of the respective lithium-ion battery cell.

In the third embodiments or any other embodiment, at least oneultrasound sensor is arranged to detect ultrasound transmitted throughan interior of the respective lithium-ion battery cell.

In the third embodiments or any other embodiment, the battery pack isconstructed for use in an automotive vehicle.

In one or more fourth embodiments, a health monitoring device comprisesan ultrasound source and an ultrasound sensor. The ultrasound source isconfigured to generate and direct ultrasound at an energy storagedevice. The ultrasound sensor is configured to detect ultrasoundreflected from or transmitted through the energy storage device and togenerate a signal responsive to the detected ultrasound from the energystorage device.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a couplant arranged between the ultrasoundsource and the energy storage device, and/or a couplant arranged betweenthe energy storage device and the ultrasound sensor.

In the fourth embodiments or any other embodiment, the ultrasonic sourcecomprises a couplant that contacts a surface of the energy storagedevice, and/or the ultrasonic sensor comprises a couplant that contactsa surface of the energy storage device.

In the fourth embodiments or any other embodiment, the couplantcomprises hydrocarbon grease or an encapsulated gel.

In the fourth embodiments or any other embodiment, the ultrasound sourceand the ultrasound sensor are disposed on a same surface of the energystorage device and spaced from each other.

In the fourth embodiments or any other embodiment, the surface of theenergy storage device is spherical, elliptical, oval, or rectangular.

In the fourth embodiments or any other embodiment, the ultrasound sourceand the ultrasound sensor are part of a single transducer, and theultrasound sensor is arranged to detect ultrasound reflected from aninterior of the energy storage device.

In the fourth embodiments or any other embodiment, the ultrasound sourceis disposed opposite to the ultrasound sensor with the energy storagedevice therebetween, and the ultrasound sensor is arranged to detectultrasound transmitted through an interior of the energy storage device.

In the fourth embodiments or any other embodiment, a second ultrasoundsensor is configured to detect ultrasound reflected from the energystorage device, and the ultrasound source and the second ultrasoundsensor are part of a single transducer.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a plurality of additional ultrasound sensors.Each additional ultrasound sensor is configured to detect ultrasoundreflected from or transmitted through the energy storage device, theultrasound sensor. The plurality of additional ultrasound sensors arearranged in an array.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises at least one additional ultrasound source andat least one additional ultrasound sensor. Each additional ultrasoundsource is configured to generate and direct ultrasound at the energystorage device. Each additional ultrasound sensor is configured todetect ultrasound reflected from or transmitted through the energystorage device and to generate a signal responsive to the detectedultrasound from the energy storage device.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a control unit configured to determine a stateof health of the energy storage device based on signals from theultrasound sensor and the at least one additional sensor.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a control unit that receives the signal fromthe ultrasound sensor. The control unit is configured to determine astate of health of the energy storage device responsive to said signal.

In the fourth embodiments or any other embodiment, the energy storagedevice comprises a battery cell and the control unit is configured todetermine the state of health of the battery cell.

In the fourth embodiments or any other embodiment, the energy storagedevice comprises a lithium-ion battery cell and the control unit isconfigured to determine the state of health of the lithium-ion batterycell.

In the fourth embodiments or any other embodiment, the ultrasound sourceor the ultrasound sensor comprises the control unit.

In the fourth embodiments or any other embodiment, the ultrasound sourceand the ultrasound sensor are separate from the control unit.

In the fourth embodiments or any other embodiment, the energy storagedevice is a battery cell within a battery pack that includes a pluralityof individual battery cells. The control unit comprises a batterymanagement system for the battery pack, and the control unit is furtherconfigured to determine a state of health of the battery pack based onthe signal from the ultrasound sensor.

In the fourth embodiments or any other embodiment, the control unit isconfigured to control the ultrasound source and the ultrasound sensor toperform an A-scan and to determine the state of health based on at leastone of amplitude of the detected ultrasound and timing of the detectedultrasound.

In the fourth embodiments or any other embodiment, the generated anddetected ultrasound comprises one or more ultrasonic pulses having afrequency greater than 1 MHz.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a testing platform and a selection device. Thetesting platform comprises the ultrasound source and the ultrasoundsensor. The selection device selects individual energy storage devicesfrom a plurality of energy storage devices for respective assessment bythe ultrasound source and the ultrasound sensor of the testing platform.

In the fourth embodiments or any other embodiment, the selection devicecomprises a conveying system that moves the individual energy storagedevices from the plurality of energy storage devices to the testingplatform for the respective assessment.

In the fourth embodiments or any other embodiment, the conveying systemcomprises a conveyor belt or reel.

In the fourth embodiments or any other embodiment, the health monitoringdevice further comprises a control unit that receives the signal fromthe ultrasound sensor and determines a state of health of the energystorage device responsive to said signal. The control unit controls theconveying system to direct energy storage devices from the testingplatform responsive to the determined state of health from therespective assessment.

In the fourth embodiments or any other embodiment, the health monitoringdevice is constructed as a handheld unit with the ultrasound source andthe ultrasound sensor disposed therein.

In the fourth embodiments or any other embodiment, the energy storagedevice comprises a battery cell. The health monitoring device furthercomprises a second sensor configured to measure battery cell internalresistance, battery cell discharge profile, battery cell charging time,battery cell current or voltage, battery cell temperature, battery cellstrain, battery cell dimensions, or gas venting from the battery celland to generate a measurement signal responsively thereto.

In the fourth embodiments or any other embodiment, the energy storagedevice is one of a plurality of battery cells, and the second sensor isarranged to monitor a different battery cell from that monitored by theultrasound sensor at a same time.

In the fourth embodiments or any other embodiment, the energy storagedevice is one of a plurality of battery cells, and the second sensor andthe ultrasound sensor monitor the same battery cell.

In the fourth embodiments or any other embodiment, the energy storagedevice comprises a lithium-ion battery cell with multiple electrodelayers, and the ultrasound source is arranged so as to direct thegenerated ultrasound perpendicular to a plane of one or more of theelectrode layers.

In the fourth embodiments or any other embodiment, at least theultrasound source is coupled to a surface of the energy storage deviceso as to move with said surface.

In one or more fifth embodiments, a method of monitoring an energystorage device comprises applying ultrasound to an energy storagedevice, detecting ultrasound reflected from or transmitted through theenergy storage device, and generating a signal indicative of thedetected ultrasound.

In the fifth embodiments or any other embodiment, the applyingultrasound to the energy storage device is via an ultrasonic sourcethrough a first couplant or the detecting ultrasound from the energystorage device is via an ultrasound sensor through a second couplant.

In the fifth embodiments or any other embodiment, the first couplant orthe second couplant comprises hydrocarbon grease, an encapsulated gel,or a gel pad.

In the fifth embodiments or any other embodiment, the applying anddetecting ultrasound comprises applying and detecting one or moreultrasonic pulses having a frequency greater than 1 MHz.

In the fifth embodiments or any other embodiment, the energy storagedevice comprises a battery cell, for example, a lithium-ion batterycell.

In the fifth embodiments or any other embodiment, the method furthercomprises determining a state of health of the energy storage devicebased at least in part on the generated signal indicative of thedetected ultrasound.

In the fifth embodiments or any other embodiment, the determining astate of health is based on at least one of amplitude of the detectedultrasound and timing of the detected ultrasound.

In the fifth embodiments or any other embodiment, the energy storagedevice is a battery cell within a battery pack that includes a pluralityof individual battery cells. The method further comprises measuringbattery cell internal resistance, battery cell discharge profile,battery cell charging time, battery cell current or voltage, batterycell temperature, battery cell strain, battery cell dimensions, or gasventing of one of the battery cells. The method additionally comprisesgenerating a measurement signal indicative of a result of saidmeasuring, and determining a state of health of the battery pack basedon the measurement signal and the signal indicative of the detectedultrasound.

In the fifth embodiments or any other embodiment, the measuring of oneof the battery cells is of a different battery cell than the detectingultrasound.

In the fifth embodiments or any other embodiment, the measuring of oneof the battery cells is of a same battery cell as the detectingultrasound.

In the fifth embodiments or any other embodiment, the energy storagedevice comprises a battery cell with multiple electrode layers, and theapplying ultrasound comprises directing ultrasound perpendicular to aplane of at least one of the electrode layers.

In the fifth embodiments or any other embodiment, the detectingultrasound that is reflected from or transmitted through the energystorage device comprises detecting ultrasound reflected from an interiorof the energy storage device.

In the fifth embodiments or any other embodiment, the detectingultrasound that is reflected from or transmitted through the energystorage device comprises detecting ultrasound transmitted through aninterior of the energy storage device.

In the fifth embodiments or any other embodiment, the applyingultrasound and the detecting ultrasound are such that an A-scan isperformed on the energy storage device.

In the fifth embodiments or any other embodiment, the applying and thedetecting ultrasound comprises disposing an ultrasound source and anultrasound sensor on a same surface of the energy storage device.

In the fifth embodiments or any other embodiment, the ultrasound sourceand sensor are part of a same transducer.

In the fifth embodiments or any other embodiment, the ultrasound sourceand sensor are spaced from each other on the same surface.

In the fifth embodiments or any other embodiment, the surface of theenergy storage device is spherical, elliptical, oval, or rectangular.

In the fifth embodiments or any other embodiment, the applying and thedetecting ultrasound comprises disposing an ultrasound source and anultrasound sensor opposite from each other with the energy storagedevice therebetween.

In the fifth embodiments or any other embodiment, the method furthercomprises attaching a couplant to an ultrasonic source configured togenerate ultrasound or to the energy storage device, and arranging oneor more ultrasound sensors to receive ultrasound reflected from ortransmitted through the energy storage device.

In the fifth embodiments or any other embodiment, the method furthercomprises mounting an ultrasonic source with an integral couplant on anexternal surface of the energy storage device. The ultrasonic source isconfigured to generate ultrasound. The mounting is such that thecouplant and the ultrasonic source move with the external surface of theenergy storage device.

In the fifth embodiments or any other embodiment, the method furthercomprises, after the applying and detecting, repeating the applying andthe detecting on a second energy storage device and generating a secondsignal indicative of the detected ultrasound from the second energystorage device.

In the fifth embodiments or any other embodiment, the method furthercomprises, before the repeating, at least one of moving the secondenergy storage device to a testing platform supporting an ultrasoundsource that generates ultrasound and one or more ultrasound sensors, andmoving the testing platform supporting the ultrasound source and the oneor more ultrasound sensors to the second energy storage device.

In the fifth embodiments or any other embodiment, the method furthercomprises, after the repeating the applying and the detecting on thesecond energy storage device, directing the second energy storage devicefrom the testing platform based on the second signal.

In the fifth embodiments or any other embodiment, the method furthercomprises, at a same time as the applying and the detecting ultrasound,at least one of charging the energy storage device, discharging theenergy storage device, and repeatedly charging and discharging theenergy storage device.

In the fifth embodiments or any other embodiment, the method furthercomprises measuring at least one of discharge profile of the energystorage device, charging time of the energy storage device, current orvoltage of the energy storage device, temperature of the energy storagedevice, strain levels on the energy storage device, dimensions or changein dimensions of the energy storage, internal resistance of the energystorage device, and venting of gas from the energy storage device via agas vent sensor or strain measurements.

In the fifth embodiments or any other embodiment, the energy storagedevice is a battery cell within a battery pack that includes a pluralityof individual battery cells. The method further comprises determining astate of health of the battery pack based at least in part on thegenerated signal.

In the fifth embodiments or any other embodiment, the applying and thedetecting ultrasound comprise supporting by hand an ultrasound source oran ultrasound sensor with respect to the energy storage device.

In the fifth embodiments or any other embodiment, the energy storagedevice comprises a battery cell with multiple electrode layers, and theapplying ultrasound comprises directing generated ultrasoundperpendicular to a plane of one or more electrode layers.

In any of the embodiments, a system can be configured to perform anymethod disclosed herein.

In any of the embodiments, a non-transitory computer-readable storagemedium is embodied with a sequence of programmed instructions, and acomputer processing system executes the sequence of programmedinstructions embodied on the computer-readable storage medium to causethe computer processing system to perform any of the methods disclosedherein.

It will be appreciated that the modules, processes, systems, and devicesdescribed above, for example, the control unit, can be implemented inhardware, hardware programmed by software, software instruction storedon a non-transitory computer readable medium or a combination of theabove. For example, a method for determining a state of health of one ormore battery cells using ultrasonic assessment can be implemented, forexample, using a processor configured to execute a sequence ofprogrammed instructions stored on a non-transitory computer readablemedium. For example, the processor can include, but is not limited to, apersonal computer or workstation or other such computing system thatincludes a processor, microprocessor, microcontroller device, or iscomprised of control logic including integrated circuits such as, forexample, an Application Specific Integrated Circuit (ASIC). Theinstructions can be compiled from source code instructions provided inaccordance with a programming language such as Java, C++, C#.net or thelike. The instructions can also comprise code and data objects providedin accordance with, for example, the Visual BasicTM language, LabVIEW,or another structured or object-oriented programming language. Thesequence of programmed instructions and data associated therewith can bestored in a non-transitory computer-readable medium such as a computermemory or storage device which may be any suitable memory apparatus,such as, but not limited to read-only memory (ROM), programmableread-only memory (PROM), electrically erasable programmable read-onlymemory (EEPROM), random-access memory (RAM), flash memory, disk driveand the like.

Furthermore, the modules, processes, systems, and devices, for example,the control unit, can be implemented as a single processor or as adistributed processor. Further, it should be appreciated that the stepsmentioned herein may be performed on a single or distributed processor(single and/or multi-core). Also, the processes, modules, andsub-modules described in the various figures of and for embodimentsherein, for example, the control unit, may be distributed acrossmultiple computers or systems or may be co-located in a single processoror system. Structural embodiment alternatives suitable for implementingthe modules, systems, or processes described herein, for example, thecontrol unit, are provided below.

The modules, processes, systems, and devices described above, forexample, the control unit, can be implemented as a programmed generalpurpose computer, an electronic device programmed with microcode, ahard-wired analog logic circuit, software stored on a computer-readablemedium or signal, an optical computing device, a networked system ofelectronic and/or optical devices, a special purpose computing device,an integrated circuit device, a semiconductor chip, and a softwaremodule or object stored on a computer-readable medium or signal, forexample.

Embodiments of the methods, processes, modules, devices, and systems (ortheir sub-components or modules), for example, the control unit, may beimplemented on a general-purpose computer, a special-purpose computer, aprogrammed microprocessor or microcontroller and peripheral integratedcircuit element, an ASIC or other integrated circuit, a digital signalprocessor, a hardwired electronic or logic circuit such as a discreteelement circuit, a programmed logic circuit such as a programmable logicdevice (PLD), programmable logic array (PLA), field-programmable gatearray (FPGA), programmable array logic (PAL) device, or the like. Ingeneral, any process capable of implementing the functions or stepsdescribed herein can be used to implement embodiments of the methods,systems, or computer program products (software program stored on anon-transitory computer readable medium).

Furthermore, embodiments of the disclosed methods, processes, modules,devices, systems, and computer program product, for example, the controlunit, may be readily implemented, fully or partially, in software using,for example, object or object-oriented software development environmentsthat provide portable source code that can be used on a variety ofcomputer platforms. Alternatively, embodiments of the disclosed methods,processes, modules, devices, systems, and computer program product, forexample, the control unit, can be implemented partially or fully inhardware using, for example, standard logic circuits or avery-large-scale integration (VLSI) design. Other hardware or softwarecan be used to implement embodiments depending on the speed and/orefficiency requirements of the systems, the particular function, and/orparticular software or hardware system, microprocessor, or microcomputerbeing utilized. Embodiments of the methods, processes, modules, devices,systems, and computer program product, for example, the control unit,can be implemented in hardware and/or software using any known or laterdeveloped systems or structures, devices and/or software by those ofordinary skill in the art from the function description provided hereinand with knowledge of battery assessment or health monitoring systemsand/or computer programming arts.

Furthermore, the foregoing descriptions apply, in some cases, toexamples generated in a laboratory, but these examples can be extendedto production techniques. For example, where quantities and techniquesapply to the laboratory examples, they should not be understood aslimiting. In addition, although specific chemicals and materials havebeen disclosed herein, other chemicals and materials may also beemployed according to one or more contemplated embodiments.

Features of the disclosed embodiments may be combined, rearranged,omitted, etc., within the scope of the invention to produce additionalembodiments. Furthermore, certain features may sometimes be used toadvantage without a corresponding use of other features.

It is thus apparent that there is provided in accordance with thepresent disclosure, system, methods, and devices for monitoring a stateof health of an energy storage device, such as a lithium-ion batterycell. Many alternatives, modifications, and variations are enabled bythe present disclosure. While specific embodiments have been shown anddescribed in detail to illustrate the application of the principles ofthe present invention, it will be understood that the invention may beembodied otherwise without departing from such principles.

Accordingly, Applicants intend to embrace all such alternatives,modifications, equivalents, and variations that are within the spiritand scope of the present invention.

1-25. (canceled)
 26. An apparatus, comprising: one or more firsttransducers for interrogating a test battery; a test platform configuredto couple the one or more first transducers to the test battery; a firstsupport extending from the test platform; a first transducer supportassembly coupled to the first support and constructed to support the oneor more first transducers between the first support and a first externalsurface of the test battery; and one or more pressure applying devicesconfigured to apply a biasing force to urge the one or more firsttransducers toward the first external surface of the test battery. 27.The apparatus of claim 26, wherein the first support is movable withrespect to the test platform.
 28. The apparatus of claim 26, furthercomprising: one or more second transducers for interrogating the testbattery; a second support extending from the test platform; and a secondtransducer support assembly coupled to the second support andconstructed to support the one or more second transducers between thesecond support and a second external surface of the test battery. 29.The apparatus of claim 28, wherein the one or more pressure applyingdevices are configured to apply a biasing force to urge each of the oneor more first transducers toward the first external surface of the testbattery and to urge each of the one or more second transducers towardthe second external surface of the test battery.
 30. The apparatus ofclaim 28, wherein the first support is movable with respect to the testplatform.
 31. The apparatus of claim 28, wherein the second support ismovable with respect to the test platform.
 32. The apparatus of claim28, further comprising a temperature sensor configured to measuretemperature of the test battery.
 33. The apparatus of claim 28, furthercomprising a couplant located between the one or more second transducersand the second external surface of the test battery.
 34. The apparatusof claim 28, wherein: each of the one or more first transducerscomprises an ultrasound pulse generator source constructed to direct anultrasound source signal into an interior of the test battery throughthe first external surface of the test battery, each of the one or moresecond transducers comprises an ultrasound sensor constructed to detectultrasound energy received from the interior of the test battery throughthe second external surface of the test battery and to generate a testsignal responsive to the detected ultrasound energy, and the detectedultrasound energy comprises a portion of the ultrasound source signalfrom at least one of the one or more first transducers that istransmitted through the test battery interior.
 35. The apparatus ofclaim 34, wherein the one or more pressure applying devices areconfigured to apply a biasing force to urge each of the one or morefirst transducers toward the first external surface of the test batteryand to urge each of the one or more second transducers toward the secondexternal surface of the test battery.
 36. The apparatus of claim 34,wherein the first support is movable with respect to the test platform.37. The apparatus of claim 34, wherein the second support is movablewith respect to the test platform.
 38. The apparatus of claim 34,wherein the detected ultrasound energy comprises a transmission modeamplitude scan characterized by a test signal amplitude component and atime interval component.
 39. The apparatus of claim 34, wherein the testsignal comprises a stream of test signal amplitude values, each of whichhas a corresponding time interval value, and wherein each time intervalcommences with initiation of the corresponding ultrasound source signaland ends at a time when the corresponding ultrasound energy is detectedby the ultrasound sensor.
 40. The apparatus of claim 34, furthercomprising: a controller in communication with at least one of theultrasound pulse generator source and the ultrasound sensor, wherein thecontroller is configured to control each ultrasound pulse generatorsource to initiate energy pulse emissions for the correspondingultrasound source signal, and to receive the test signal responsive tothe detected ultrasound energy from each ultrasound sensor.
 41. Theapparatus of claim 40, wherein the controller is configured to comparethe test signal for the test battery, or data extracted from the testsignal, with one or more previously-obtained test signals, or dataextracted from the one or more previously-obtained test signals, todetermine a state of health of the test battery.
 42. The apparatus ofclaim 34, further comprising a controller configured to compare the testsignal for the test battery, or data extracted from the test signal,with one or more previously-obtained test signals, or data extractedfrom the one or more previously-obtained test signals, to determine astate of health of the test battery.
 43. The apparatus of claim 42,wherein the controller is further configured to generate a signal basedon the determined state of health.
 44. The apparatus of claim 34,wherein the test battery interior comprises one or more battery cells,each of which is formed by a plurality of material layers arranged inparallel electrode layer planes, and wherein the ultrasound sourcesignals from the one or more first transducers are directedsubstantially perpendicular to the parallel electrode layer planes. 45.The apparatus of claim 26, wherein each of the one or more firsttransducers comprises: an ultrasound pulse generator source portionconstructed to direct an ultrasound source signal into an interior ofthe test battery through the first external surface of the test battery;and an ultrasound sensor portion constructed to detect ultrasound energyfrom the interior of the test battery through the first external surfaceof the test battery and to generate a test signal responsive to thedetected ultrasound energy, and wherein the detected ultrasound energycomprises a portion of the ultrasound source signal that is reflected bythe test battery interior back toward the one or more first transducers.46. The apparatus of claim 45, wherein the detected ultrasound energycomprises a pulse echo mode amplitude scan characterized by a testsignal amplitude component and a time interval component.
 47. Theapparatus of claim 45, further comprising: a controller coupled to eachultrasound generator source portion and each ultrasound sensor portion,wherein the controller is configured to control each ultrasoundgenerator source portion to initiate the corresponding ultrasound sourcesignal and to receive the test signal responsive to the detectedultrasound energy from each ultrasound sensor portion.
 48. The apparatusof claim 45, further comprising a controller configured to compare thetest signal for the test battery, or data extracted from the testsignal, with one or more previously-obtained test signals, or dataextracted from the one or more previously-obtained test signals, todetermine a state of health of the test battery.
 49. The apparatus ofclaim 45, wherein the test signal comprises a stream of test signalamplitude values, each of which has a corresponding time interval value,and wherein each time interval commences with initiation of thecorresponding ultrasound source signal and ends at a time when thecorresponding ultrasound energy is detected by the ultrasound sensorportion.
 50. The apparatus of claim 45, wherein the test batteryinterior comprises one or more battery cells, each of which is formed bya plurality of material layers arranged in parallel electrode layerplanes, and wherein the ultrasound source signals from the one or moreof the ultrasound pulse generator source portions are directedsubstantially perpendicular to the parallel electrode layer planes. 51.The apparatus of claim 26, further comprising a temperature sensorconfigured to measure temperature of the test battery.
 52. The apparatusof claim 26, further comprising a couplant located between the one ormore first transducers and the first external surface of the testbattery.
 53. A battery testing method comprising: placing a test batteryin a test apparatus, the test apparatus comprising a first supportsupporting one or more first transducers, each first transducer beingconfigured for interrogation of the test battery via one or morepulse-echo mode signals; positioning the first support in a testingposition for coupling each of the one or more first transducers to anexternal surface of the test battery; and applying, by one or morepressure applying devices, a biasing force that urges each of the one ormore first transducers toward the first external surface of the testbattery.
 54. A battery testing method comprising: placing a test batteryin a test apparatus, the test apparatus comprising a first supportsupporting one or more first transducers and a second support supportingone or more second transducers, the first transducers and the secondtransducers being configured for interrogation of the test battery viaone or more transmission mode signals; positioning the first support ina first testing position for coupling each of the one or more firsttransducers to a first external surface of the test battery; positioningthe second support in a second testing position for coupling each of theone or more second transducers to a second external surface of the testbattery; and applying, by one or more pressure applying devices, abiasing force that urges each of the one or more first transducerstoward the first external surface of the test battery and that urgeseach of the one or more second transducers toward the second externalsurface of the test battery.